Hate to disappoint you TMS, but most of those games work smoothly on a single 256-bit 8600M GT, 4MB DDR RAM, 2.5 GHz Dual core processor and a 250GB 7200 rpm HDD. My laptop handles it easily on the highest settings (albeit a few fps slowdowns from rapidly moving the mouse...And the Internet. Gotta find the cause of that.)
Crysis is what makes you need higher-end gaming computers though. Also, if you listen to the commentary on Portal, they took measures to make sure the game doesn't use massive resources, especially when looking into the Portals.
But great find Zem. The only thing I can find wrong with it is that it's not portable ; but yet, I will be creating my own comp soon (I've got a required course that deals with that). Hopefully it's not a crappy deal, like recycled parts or something that will make it impossible to get it working because of the incompatibilities.
(Speaking of which, I'm up for TF2 now...)
I think he meant that you would need a larger hard drive to keep the games (which tend to have large files) on, rather than it effecting how well the games play.