I got my start playing Wolfenstein 3D and Doom.
Doom3 was a great game, I loved it tremendously and for the time it was beautiful. It was so terrifying to play it on high-highest settings with a good sound system in the dark.
I really liked how they didn't resort to the "oh shit, something's killing me from behind!" sort of scares. That always seems incredibly cheap and unnecessary in a horror game.
The only problem... it got repetitive. The game was too long to keep the same gameplay from getting old after a while.
As for graphics... Crysis is pretty damn realistic, but there are always a couple of places to improve. The lighting in some areas of Crysis bothered me a bit, and some of the snow and fog effects seemed... faked. The alien ship especially could have used some improvement. The visuals in the last boss fight seemed to have been rushed pretty badly too.
It's all nitpicky, but it seems like in every generation of game there's one or two that no one thinks could ever be beaten for graphics and every time the next generation beats the hell out of it.
I'm pretty sure that Doom4 is gonna be another "it's done when it's done" game. Personally I'm glad, there've been far too many excellent game concepts that just go to waste because the developers were on a tight deadline and rushed it.
By the way, I could run Doom3 at highest settings at 1280x1024 or 1600x1200 with 4xaa just fine on a pair of overclocked 7600GTs getting 20-60fps. I'm kind of surprised your 7800 was having trouble. 16x AA is unnecessary, and I mean completely unnecessary. Even at 1024x768 and 800x600 you can't notice a difference between 8x and 16x even on close up straight edges. If you're running at 640x480... bump up that resolution and drop the AA. That much post processing is going to seriously and unnecessarily harm performance in any game.
Opteron 175 @ 2.83ghz
2GB DDR 400 @ 333 CAS 2-2-2
2x80gb sata2 drives RAID0 for audio editing and OS
1x120gb IDE drive storage
MSI k8n Diamond Plus
M-Audio Fast Track Ultra
19" flat CRT (Monstrously heavy monitor)
I use Blender, Ableton Live, GIMP, AND play games on this thing. Shove your resource intensive operating systems.