It depends what you want it for. When I graduated college and built myself a nice computer I got a P183 and it was definitely worth it; installation was easier and it's much quieter than my no-name cases of the past. But for most people I'd say ease of installation is not worth $100-plus and the noise only became a factor for me when I moved out of dorm housing.
There definitely are some cases at around the $50 mark that will offer most of the benefits of a premium case if you do your research, and the benefits they provide may be all you care about.
Core i7 920, 3x2GB Corsair DDR3 1600, 80GB X25-M, 1TB WD Caviar Black, MSI X58 Pro-E, Radeon 4890, Cooler Master iGreen 600, Antec P183, opticals