Winter: take warm clothing. it snows and rains most of the winter and gets very cold. most houses, stores, and public places are not well heated. thick jackets, gloves, hats, and boots are a must from late november to around March: it depends, every years varies slightly.
Summer: during the day it is extremely hot. no one sensible enough goes outside. it cools a bit in the afternoon and might even get a bit chilly at night so take a couple of sweaters or a light jacket. it does NOT rain in the summer so don't worry about rain gear.
any season: take a pair of shoes and don't miss out on a hike in the nearby mountains.
Toiletries and Medical Supplies: you can find all the medical supplies your heart desires in any pharmacy in syria. for ladies, tampons might be hard to find over there so if that's your thing, bring your own. shampoos, soap, and other are in abundance and there are many european brands. the only thing to bring is body lotions and hand creams if you have specific preferences. also, i'm alergic to most brands of lip balm so i always make sure i have my own supply with me just in case i don't find the brand i need...
Photo Equipment: cameras aren't expensive there but take your own. if you happen to forget yours you can find 'camera stores' all over the place. they sell cameras and develop film. i would advice that you don't develop the films there as the quality isn't that good and when bying films: check the expiration date. as for digital cameras, they can be a bit expensive...
Camping/Beach/Outdoor Gear: there are a few pools in the area so bring your swimsuit. for the ladies, i advice nothing too revealing or you might get un needed attention
bring along hiking shoes for the mountains and long jeans. definetly long jeans as there is quite a few prickly bushes and some friendly bugs :)