Daytime is hot, so shorts, skirts, tees are all ok, as a summer dresses and should definitely be packed. Keep in mind that you should have something less revealing in your suitcase for visiting churches - it can get quite strict. The evenings were a bit on the chilly side, so would suggest long trousers/shorts, as well as a cardigan. Comfortable shoes are a must.
There is good hiking nearby, so of you're into that consider outdoor clothing.
Toiletries and Medical Supplies: Unless you need something special or a particular brand, these things are easily obtained.
Photo Equipment: Definitely a camera and lots of space on a memory card (it's cliche, I know). Streets are narrow so if you have a DSLR camera, take a wide-angle lens of you have one, it's difficult to fit subjects in the frame without it. Also, a tripod if you're into photography - the town looks much better at nighttime.
Camping/Beach/Outdoor Gear: Just clothing will be enough if you're into hiking.
Miscellaneous: I know that the most they don't know where is Matera......so i put a map that can give you an idea about the location of the town.....