This is probably the best guide for the Khymer temples near Siem Reap, and the best news is that it is free. Just download it from the above link, at it's totally legal. It is the English translation of Maurice Glaize's 1944 book.
Luggage and bags:
I carry a small day backpack for my essentials:
AS MALARIA AND DENGUE FEVER IS PREVALENT IN THESE AREAS IT IS BEST TO USE A GOOD STRONG AND RELIABLE REPELLANT
ALWAYS CARRY ENOUGH WATER FOR THE TIME NEEDED..
MAKE SURE YOU HAVE A GOOD MOSQUITO AND INSECT REPELLANT WITH YOU.
Clothing/Shoes/Weather Gear: WEAR A GOOD PAIR OF WALKING/HIKING BOOTS
A GOOD HAT AS THE SUN CAN BE EXTREME
A PAIR OF SUNGLASSES
A SMALL ROLLED UP PONCHO
Toiletries and Medical Supplies: A TUBE GOOD SUNSCREEN
A TUBE OF GOOD MOISTURISER
A SMALL STICK LIPBALM
A PACKET OF WETONES
A SMALL PACKET OF TISSUES..
Photo Equipment: A DIGITAL CAMERA BATTERY CHARGER
A SPARE MEMORY CARD
AN INTERNATIONAL POWER POINT ADAPTOR
Camping/Beach/Outdoor Gear: ALWAYS CARRY A SMALL SELF CHARGING TORCH
I ALWAYS CARRY A BACKUP PAIR OF GLASSES
Miscellaneous: Even though I bought a copy of Lonely Planet with me, it wasn't all that good with pictures or detail. I was browsing a copy of book shops in Siem Reap, at the old market and found many books on Angkor that are sold as counterfeit (copies). I decided to by one called The Treasures of Angkor by Marilia Albanese for just a few dollars and it really goes into a lot of detail on each temple site with lots of glossy colour photos and plans.
Luggage and bags:
Carry a small backpack when you're walking around especially when visiting the temples. It's convenient to put in the lil' items that you'll buy from the peddlers just outside the temples.
If you're going for a 3 to 4 day trip just to Siem Reap/ Angkor Wat... you don't need to pack much, 2 pair of shorts, 5- 6 t-shirts, a cap, sunglasses, comfy shoes, don't forget your sunblock and camera!
Clothing/Shoes/Weather Gear: Wear sport shoes or hiking sandals.... they are the absolute best. And if you're planning to visit in the summer months, carry and extra pair of socks...Light clothing during summer, shorts and t- shirt, bring along and extra pair, cuz trust me! You'll need them and feel a lot more comfortable. And for the women! Wear your sports bra, you'll feel a whole lot more comfy. Also, don't forget to pack a cap and a hand towel.
Toiletries and Medical Supplies: I brought along a small first aide kit (the ones that comes in those zip pouches) they come in handy especially if you're clumsy like me and are prone to getting lil' cuts and bruises on your hands and legs.
Photo Equipment: Gosh... a good digital camera... with an extra memory card!! You'll never get enough of the sites. And don't forget an extra battery that is fully charged. You'll be trigger happy!!
Luggage and bags:
Travel light. Don't bring anything heavy.
Clothing/Shoes/Weather Gear: Wear light clothes, something that let's your skin breathe. Something with omni-control or those clothes with wick-away capabilities. :) This will help make you more comfortable despite the heat and humidity. Bring shoes which will be comfortable for walking through dirt-packed forest trails, up narrow temple steps and slippery market alleyways. But always keep in mind that your footwear should be comfortable in hot weather. :) Bring a wide-brimmed hat because the sun is very fierce even for Asian skin like mine. I can just imagine what it can do to western skin.
Toiletries and Medical Supplies: It you need special medicine then bring them with you. For everything else you can get from the groceries that line the main street.
Photo Equipment: Bring chargers and extra batteries with you. Keep your cameras in weather-proof cases as rain showers often come in the afternoons.
Luggage and bags:
A light day bag to carry you snacks, water bottles and all the crap you'll buy from the vendors
Clothing/Shoes/Weather Gear: Hiking shoes for climbing
Toiletries and Medical Supplies: hand sanitizers, baby wipes, sunscreen, mosquito repellent (although I don't remember encountering many in January when I went), small first aid kit
Photo Equipment: Lots and Lots
Miscellaneous: Small bill denominations if you're using dollars, and strong bargaining skills!
Miscellaneous: Make sure you have a bottle of water with you. Due to heat and lots of exploring you can easily get dehydrated. Do not drink water from the tab unless advise. Water can be purchase from the street seller, but cost USD1 per bottle is not really worthy right?
Toiletries and Medical Supplies:
As an emerging economy, will be difficult to find toiletries of your preference and medication outside the major towns. So better top up in Bangkok or from your home destination.
Miscellaneous: Found my "Lonely Planet" extremely useful in my unplanned trip. It is worth the weight to carry around. Bought it in Bangkok, not sure if easily available in Cambodia.
First, protection from the sun. Sunscreen on every exposed part of your skin. Including your ears, which can get sunburnt. Cap/ hat to prevent getting a sunburnt scalp, and shades to help you enjoy the reliefs more without the sunglare. Extra tip: get a pair of brown shades instead of the normal black ones. Apparently it emphasises the detailing of carvings amazingly. Definitely a bonus I realised when I found my brown shades enhances my visual experience.
Second, if you are considering travelling in a tuk-tuk, bring a scarf large enough for you to tie it around your head. Fret not about appearing like a freak with your head all wrapped up, it is much better than breathing in too much dust or having to hold your hands up to cover up your mouth with a small piece of tissue throughout the whole trip. Of course, when it is not so dusty I do take in some fresh air along the way.
Miscellaneous: Thirdly, the tourist crowd is everywhere, especially at the entrance where you get your entry pass to the temples. Get ready a passport size photo so you can skip the queue to take your photo for the pass. And get good walking shoes to help you get to the unbeaten path away from the crowd that will require some climbing and walking over loose rocks.
Luggage and bags:
Get a small backpack that can fit in a trusty guide book and a regular water bottle, you'll need it in the heat. You do not have to worry about bringing a few guide books before you leave for Siem Reap. Lonely Planet Cambodia is a good enough general guide to count on. For more detailed information on Angkor Temples, 'Ancient Angkor' often sold by the children at the temples is a great guide you can get at a low price, if you bargain.
Clothing/Shoes/Weather Gear: Wear light comfortable clothes that you can move easily when climbing the many steps. A tip I learnt is that you do not have to worry about having changes of bottoms. With all the physical and sometimes on all fours climbing to do, it will get dirty within your first climb. Get a trusty pair of bottoms and live with it for days. It helps you take your mind off worrying whether you will dirty your pants while climbing up those steep steps. If you are tired, you need not think much about resting your bum on those steps either. Plus, you will be thankful when you are back home with less load to wash.
Luggage and bags:
Exploring the Angkor temples require a lot of walking and climbing around. So please bring along a small to medium sized backpack or daypack for you to put your necessities in as you wander about the place. You would want to keep your hands free so you can navigate your way around those dark corridors and steep steps. Keep those shoulder sling bags at home.
Clothing/Shoes/Weather Gear: A good pair of sports or running shoes (Slippers won't make it unless you are looking to get your toes cut by some boulder or rock).
Dress in a T-shirt and bermudas or shorts. Jeans might get rather stuffy and uncomfortable once you start sweating profusely.
Bring along your sunglasses, a cap or a hat as it can get really hot in midday. A bottle of sunblock lotion is highly recommended.
If you are going during the monsoon season (October to December), you might want to bring along a waterproof windbreaker or a raincoat as the skies just rip open their floodgates without warning.
Toiletries and Medical Supplies: OK, this may sound silly but be sure to bring packets of tissue paper with in case you ever need to take a crap in one of the toilets around Angkor. Some of the toilets don't have any toilet paper at all. Fortunately, I didn't need to do anything beyond taking a leak at one of their toilets, which believe me, wasn't a pleasant sight at all.
Tip: Try to do your 'business' in the comfort of your hotel's toilet every morning before you leave for your explorations.
Bring some mosquito repellant as well as Siem Reap is rather infamous for its dengue epidemic. I suppose the touristy areas are safe but when you are out hiking through the remote areas, you should apply some repellant generously, especially onto your legs.
Photo Equipment: If you do forget about this stuff, you seriously need to be shot..twice over.
Miscellaneous: Have a large bottle of water (1 litre) with you; you will need it.
Get a good guidebook on Cambodia.
Comfortable and fairly hardwearing shoes are the only sensible option when touring the temples. You can see a lot of climbing is involved and of course you want to get to the top for the best views, only getting to the top here can mean almost vertical climbs.
Remember that you will be out in the sun for a long time, even during the wet season the sun can be out for long periods so a hat is a sensible option
Krama is a Cambodian multifunction sheet.
You can: (i) use it as head protector; (ii) use it to wipe your sweat; (iii) use it to protect your neck; and (iv) use it to cover your face from dust.
The price of a cheap Krama is around US$ 1 and you can find it at local markets.
Clothing/Shoes/Weather Gear: Make sure to wear shoes which can be tramped in all day, as well as factoring in the huge number of steps - steep steps - and the general dirt and grime of it all. Open shoes would be a bit of a disaster, from my observation and experience.
Miscellaneous: Useful to have some spare passport or similar pics for when you purchase your pass to Angkor Wat - especially if you care about how you look! My kids were horrified by their wilted photos, taken after a lengthy wait at the small office at the AW admin. As I understand it, you can bring your own pic - for the aesthetics and the avoidance of yet another wait.