we just had a custom PC built for an employee of mine. She wanted a faster machine for video editing.
i dont know the exact specs, but it's the latest quad core, 8gigs ram, nvidia 285, etc...all running on XP 64. It cost only 1,500 or something ridiculously low for such a fast machine (but no keyboard, mouse, monitor, etc...just the box). Since it's for work, there are no games installed on it yet. But i'll bring in Prototype and Crysis Warhead on Monday and see how fast they can run at 1920x1200...
it's amazing how cheap fast PCs are getting. Even 2 years ago, a machine like this would have cost around 3,500-4k USD.
Btw, for desktops, you don't need Alienware. Just copy/paste their specs and have a third party built if for you using the exact same parts. You'll save about 500-1000$! Only go w/ them if you want a gaming laptop...
-feng