There are plenty of choices - mid towers are smaller and take up less space, but full towers have a lot of room inside the case which makes cabling easier/better, and your case will cool better with less effort. If you chip in another $10-20 for a full tower, it'll be worth it IMHO.
The HAF 922 and 932 are great places to start. Other good cases include the Raven RV02 and NZXT Phantom.