DELL? Smoke the competition? AHAHAHAHAAA! Yes, you might have raw processing power but only where it doesn't matter, i.e. in a Pentium 4 processor. Those things are among the least efficient processors on the market. Both power consumption and work-to-cycle ratio, a P4 is a waste of money that is designed more for marketing than usage. Seriously, get a cheap CPU and if you want high end throw the money at the graphics card and RAM. If you buy a high end Dell you pay enough to afford two custom built game machines. Look at smaller computer stores, some have much lower prices. Read a tutorial or two about building your own PC (or just read the mainboard's manual which describes 90% of the process, the rest is just plugging in monitor, keyboard and mouse).
Though a local store might even have cheap complete systems, for example the store I regularly buy my stuff from offers pretty good base systems for 500 or even 190 if you want to throw a few upgrades at it (graphics card, another 512MB of RAM, 100 for the graphics card, 40 for the RAM) and a few in between, some of which need cheap upgrades to be effective gaming rigs. 19" CRT for 100 (LCDs cost more and deliver less, a CRT, especially a 19" one delivers much better resolution, no blurring and better colors). Plug in your sound system. Add maybe 10 minimum for mouse/keyboard, depending on whether you want the basic versions or ome more expensive stuff and you're good to go.
Your local prices might go up by 80 for the PC because MS pressures retailers into selling no PC without Windows (actually without OS but few are smart enough to bundle Linux or FreeDOS), make sure they don't want to throw some office package in there, it sounds like a deal but you can get free software instead that only lacks the features you'll never need anyway and you always pay for that bundled software. All you need is Windows itself (since you're a gamer I won't try to sell you the more esoteric solution of "Linux+Cedega" that doesn't work with many games), no extras. And dont accept "repair CDs" or crap like that, insist on a full version of Windows, anything else means trouble. Dell will force a much bigger bundle on you by default and preconfigure your PC in a way that will make your games run much worse than they could.
All in all that sounds confusing but the result is much cheaper and you have much more control over it. You know who built it, you know what's in there and you know that nothing you don't want is in there (well, except for Windows' "extra functionality" like intalling random viri from the internet but Dell won't remove that either). It's really not difficult, most of the difficulty came from jumper setting and stuff back then, nowadays it's pretty much "plug everything together, power on".
And drop the "RVN" label, "RV" and "RN" are internal chip codenames by ATI, RV being a budget Radeon and RN the rumored name of the Hollywood chip. Of course with numbers appended, e.g. RV200 (Radeon 7200).