I bought an Antec case a little over two years ago, and I expect to be using it for a long time to come. It only has the 300 W PSU, but I when I first had it, I was running a Thunderbird 900 @ 1050, 3 x 7200 rpm HD (40 GB boot drive, and 2x20 in a raid 0 set), promise pci raid controller, Geforce 2 GTS, SB-Live, two optical drives, a pci nic and two case fans. The rig ran many hours in a very hot room, and was always stable. Even with the 3 HD and two optical drives, I had plenty of space for more stuff.
I have recently moved the t-bird into a lesser case now, where it can fold in relative anonymity, while the Antec hosts my T-Bred B 2200+. I expect to use this as my main case for a long time to come, probably as long as the ATX form factor survives. I would expect you will get much more than two years out of this case. If you like to swap components in and out, this case is for you.
As far as air-flow goes, I run the 2200+ at stock speed with a Thermalright SLK-900u heat-sink/Vantec Stealth 92 mm combo, and no case fans - even without case fans, the system is very stable (folding 24/7 - CPU maxed out) and near silent.
You cannot go wrong - if you want to have a raid set, you may want to look at the Antec Sonata - it has the drive cage rotated 90 degress to allow for more space internally, and neater cabling.