Hey Tindo, i didnt know you were thinking about a cham. i did a lot of research when i first got into them and decided to go with a veiled for a number of reasons. i can say that i made a wise decision and was very pleased with the cham i owned. the veileds are very temp hardy as mentioned above. they have a wide range and can tolerate temps from the upper 90s to the 50s (night drops not constant day temp), IME. if they do get down into the 50s they just need a basking spot so they can raise their temp as need be.
basking and UV are very important. i used the NO UV and UVB bulbs along with a powersun. that was the ticket. it provided a nice basking area and great UV light. the NO bulbs are only effective in like a 10-12" range away from them, so unless your cham is right up next to them, they are rather inefficent. with the powersun wattage determines the effective distance away from the bulb, but i want to say the one i had was something like 6' before loosing half of its intensity. this is essential in the taller tanks that these guys need. i kept mine in a 24x24x36 screen cage. once he was getting full grown it was too small though. i think 30x30x48 would be a good size for an adult male. of course the larger the better.
heres a shot of the tank i kept him in. its just a potted ficus tree with pothos and a small shefflera tree.
http://img.photobucket.com/albums/v6.../NewHome_B.jpg
this is a good article that was publishd in reptiles mag. it was definatly the best online care sheet back when i was looking. im sure it can help you out.
http://www.kingsnake.com/rockymounta.../RMHveiled.htm