Luggage and bags:
To carry your gear you'll need a main pack of approx 70L and a day bag big enough for food and water during game drives. My day bag is only 22L and it was easy big enough for both the Serengeti and Kilimanjaro.
Clothing/Shoes/Weather Gear: Remember that it's very dusty here so what ever you wear on your feet, if the dust can get in it will! Sports shoes (tennis shoes, runners etc) will let the dust in but will be comfortable. I'd recommend that you bring sports sandals if you have them or Jandals (thongs, flip flops) which are also really good for shower & toilet time. A wet and wind proof jacket is handy though during the day in the warmer months it get quite hot! Quick dry tee shirts and shorts will be worn mostly so bring those but remember that if you are using Malaria tabs that make you sun sensitive to cover up with a wide brimmed hat.
Toiletries and Medical Supplies: Always bring extra toilet paper! This is vital to your comfort. Medical supplies will often be part of your tour guides kit if you are doing a tour - if not then you can buy an essential kit before you leave home (bandages, insect repellant 40% deet, sunscreen, anti bacterial cream, runny bottom pills etc)
Photo Equipment: If you are like me then your main concern here is battery life of your digital camera and storage media. I had a small digital camera that used AA batteries so I never had an issue. Others brought very fancy cameras that needed recharging - our truck had a charge board so all good - will pay to check this before you decide!
Camping/Beach/Outdoor Gear: You'll need to carry a sleeping bag plus tent and ground mat unless these are provided.
Miscellaneous: A head torch is very useful as there is normally no lighting at night - unless you have a full moon lol. Also think of things such as a deck of cards and travel diary. Also good to bring is a towel, clothes washing soap and clothes line (aka spare shoe laces)
Toiletries and Medical Supplies: Clean water is essential to your health whilst in africa dont ever assume that water is safe and this also applies when brushing your teeth and showering be very careful people die here drinking bad water !!!
Because of the excellent camouflage that the serengeti grasses offer it's denizens, you will need to scout for them using your binoculars and usually, standing in your 4x4 vehicle as you drive down the serengeti dirt roads. This makes for dusty and chilly winds sometimes.
Evenings and early mornings are the best times for a game drive. That is when the big cats are out on the prowl and can be easily spotted. It's also when the weather can get chilly.
Make sure to pack a sweater and scarf to keep yourself warm.
Dust is everywhere in the Serengeti. Because of the vast openess and aridity of the plains, you will notice dust film deposits on everything. Protect your camera by covering it in a ziploc bag and keep a lens cleaner close at hand.
Also pack a no wash hand sanitizer like Purell to clean your hands of the dust before snacking.
Luggage and bags:
Depending on what your travel plans are if your purely doing a safari then going home you wont need as much , but i always travel with my mainpack and a day pack id recommend that.
Clothing/Shoes/Weather Gear: pair of thongs i like the slip on variety and a pair of good shoes joggers i find boots to bulkey and weigh more aswell i think there unnescesary. Also a light spray jacket a jumper ,good tough trousers and shorts i like the kind with lots of pockets in them and some lighten shirts cottons etc,underwear would be good aswell.
Toiletries and Medical Supplies: Make sure you bring your own toilet paper other wise you could find yourself in a messy situation ,also include anti malarial although it didnt seem a problem on the plains you will pass through infected areas,also make sure you have immodium for diarrea ,and antibiotics for skin and internal infections mainly incase of food reactions and injuries also dont forget the tropical strength insect repellent.Theres not many places to have a shower, but take your usual soaps etc .
Photo Equipment: Youll be using alot of film so make sure you have plenty , also a good zoom is a must mine wasnt very good and i regretted that,id like to video aswell next time and take spare batteries etc.
Camping/Beach/Outdoor Gear: you can hire your sleeping bags no problem at nairobi or tanzania, the other option would be a compact sleeping bag like the palm size ones etc there good enough a small pillow would be good.
Miscellaneous: Torch,deck of cards,travel diary,personal knife and fork and a mug bis good.