If its for gaming I would spend the extra on a 7800. And a good 64bit chip by AMD.
Decent memory is important too. Make sure you have enough memory. These days 512 just doesnt cut it. Get at least 1gb.
Some new games like Battlefield 2 need 2gb to run well. I recomend you get 2 sticks of 1gb.
And leave space for future upgrades.
Finaly, make sure your PSU has enough power. 500watt or more.
Get a SATA HDD. Or those 10.000rpm raptor drives.
For gaming less than 250gb is acceptable. If you plan on using the PC for anything else like movies and such, then a bigger drive is good, but if its just for gaming get a smaller drive. 180gb or 160. Not only is it cheaper but less space to access.
Similar to what i made about 2 months ago, i went with a venice 3200 as it has the same oc head room as the 3500 and 3800 i think. I got a 7800GTX and 1gb of corsair matched pair jobbie. AN8 SLI (with passive cooling) and a 200GB seagate hd.
I'm using my 3 year old 430watt Antec True power which seems to be enough.
Everything runs silky smoth, so no oc'ing yet and that on top settings with 1600x1200 with max AA, so everything is running pretty sweet. Only problem is I don't play games as much as I used too (i blame the lack of decent software).
Yup I dont play as much as I would like to but I put it down to the fact my PC struggles with game like BF2 and now I am at the point where I just cant be arsed to play because of the load times.
And I really want a new pc ...tee hee .
I am glad to here someone else went for the same build, its very incouraging.