drwex | Time for a new PC?

I'm looking at getting myself a new PC, primarily for gaming. The current one has undergone some heroic rescue efforts and it's still bombing out on me randomly. (*)

So the question is what do I want in a moderately priced gaming box? It's probably going to be a Microsoft OS, and preferably Windows XP.(**) My baseline for this right now is the Dell XPS 630 with a dual NVIDIA GeForce 9800 card. That comes with XP pre-installed - I'd rather not do my own downgrade if I don't have to. Price new from Dell is $1400.

The question is whether I can beat that without going out and building myself a white box, which I would really rather not do. I loathe messing with PC hardware and I don't mind paying for someone else to Just Make It Work.

Other things I looked at:
Dell's Optiplex line - too limited video options
Dell's Precision line - lots more expandability, but pricey. Even the low-end T3400 comes in around the same $1400.

PC Connection HP/Compaq line - doesn't let me customize the machine. The HP SmartBuy xw4600 looks pretty close in terms of specs but is weak on the graphics and only about $300 cheaper.

One option I've heard discussed, but can't seem to find reliable data on: buy a Mac and dual-boot it with my personal copy of XP installed in the other partition. That's intuitively appealing but I'd need a lot more data on current Macs and dual booting than I can find this morning.

(*) I'm pretty sure the problem is a bad video driver. The fact that my motherboard is so old I had to get a retro card for which ATI doesn't seem to make new drivers is part of the problem.
(**) I don't particularly want to start an XP-Vista debate. I just don't see what Vista buys me, and I do see a lot of problems. One of the advantages of getting a name-brand PC is that they come with licensed media to put Vista onto the box if I decide to do that later.