Another thing to watch for when buying a mobo is that there are usually several versions offered for sale. The tricked out board will have sata, raid, sound etc. etc. then there will be versions without raid, or without sata etc. The model name is NOT enough to tell you what it is, so be sure to check.
It's hard to find a case of mobo that's not ATX format these days, so you'll be ok there I think. Small towers, or slimline desktop cases could have issues with boards that aren't made small to begin with. I'd start with a medium tower as that will make it easier for you to work in without taking up a lot of space.
Fans are a variable. It depends on how much equipment is in the case, and what kind. Overclocking would also require more cooling. 2 or 3 80mm fans should do fine. A single 120mm would probably also work. Check the fan on the power supply. It should exhaust air out of the case instead of blowing in air that has been warmed by it's transformer. All other fans should be blowing into the case.
You used to have to do a lot of mod'ing to make a case vent properly but it's becoming easy to get good cases for a reasonable price.
Good websites to check:
http://www.hardocp.com
http://www.overclockers.com
http://www.sharkyextreme.com