Dude, don't buy a dell and yeah thats just my opinion, but I have very little faith in Dell products and less in their customer service. If you want an affordable rig I would recommend the following
I bought this machine and I am very happy with it, currently I run all of the Orange box on it without any trouble, also run Wow and I did install the demo for UT3 and played it without much trouble. The machine you have listed has integrated graphics if I am not mistaken, and I would not recommend that for any of newer games, frame rates won't keep up.
Also if you are getting anything with Vista, don't go with anything less than Vista Business or Ultimate Editions, again my opinion but from what I have worked on these two versions seem to be the best.