Do not get the 3800 with the 512 KB L2 Cache! It's not worth your money! For just a few bucks more you can get a 3800 x2 (L2 Cache = 2x512KB) I have the processor and regret my decision as I could have got so much more for just a few more bucks. And by a few more bucks, I mean somewhere around a "very hefty" $30. It's quite silly, really.
To add, I personally hate ATI! Utter rubbish this x700 of mine. You won't believe the problems I've had with it. All from reverting brightness settings to just plain bad performance. Well, it's not the card actually, it's been the drivers causing the problems. I've just switched over to OmegaDrivers and not too many problems so far. But heck, with this card I've learned to count on anything.
Asus. Ah, yes the never ending bashing of asus. I'm a first time Asus user, and even though I've heard plenty of people express their "love" for Asus, I still decided with it. Not too problematic, but I will let you know about the problem I had initially. It required S-ata drivers to install my Sata drive, and I had a hectic time finding these and installing them since my older computer's floppy drive is fubar'ed.