Look at Newegg.com's Enermax cases. Very high quality PSU's included (with most cases, it will say if they aren't), excellent ventilation, decent design, and VERY reasonably priced. The case in my sig was only $49 there, and its working like a dream, temps are quite low, especially considering how hot my room gets.
Its hard to imagine people spending well over $100 on a case, when something as basic as my enermax does just fine. Shop around, you really don't have to spend an arm and a leg for a good case. For a flashy case, maybe, but flashy doesnt equate to quality.