6100? pure trash if you ask me ^^ It basically has all the possibilities of the 6xxx series, but lacks the raw power to get acceptable frame rates.
It's good for use with a second monitor, though ;)

QuoteBegin-grendel+
-->That's because Nvidia bribes them to optimise for Geforce cards... Ever noticed all those Nvidia logos in game intros and loading screens? eww.
I got a Radeon 9800, works like a charm with Oblivion, even on high settings, no bugs :)

I personally think that the HD 2900 Pro is a good one to include in a ~ $650 system. Go for it.
I would maybe change that 250GB HD for 2x 120Gb (or 250Gb) in a raid system. Less loading time for everything!
Vista? Hands off! :alien:

Still too buggy for my taste. I'll change to Vista in 2-3 years at the earliest. And all that flashy eye candy makes the interface unclear and confusing, plus it soaks up a lot of resources. XP pro Sp2 (Sp3 is on the way!) is faster and more secure. Plus MS support for XP has been extended until 2014!
Just my 2 cents...