Help me build a $600-700 gaming machine

I haven't built a computer in over 5 years so I'm not very up to date with the latest technology. I was hoping I could get some help with a build. My budget is not super strict, but I'd like to not spend much more than $700, ideally less than that. I'm looking to play some of the latest games (even if I have to play them at < optimal settings), web, poker, dvd burning, etc.

I saw the $500 gaming machine guide on this site and I figured I could use that build with a few upgrades. Here is what they recommend in that article.
Pentium Dual Core E2160 $92
Motherboard Elitegroup G33T-M2 $89
RAM Patriot PDC21G6400K, 2x 512 MB DDR2-800 $49
Graphics Card Gigabyte Radeon HD 2600 Pro $85
Hard Drive Seagate Barracuda 7200.10, SATA/300, 320 GB $65
Power Supply Silverstone ST50EF-Plus $99
Case Coolermaster Centurion 5 CAC-T05 Black/Silver $49
Other Samsung SH-S183 DVD-ROM $30
Total Cost $558

I definitely plan to upgrade to 2x1gb RAM. I'd also like to stick with Intel. Does anyone have any suggestions for what else I could upgrade? Or should I go with something completely different?

Umm....I've never overclocked before. I'd have to read and learn more about it before I feel comfortable overclocking.

In this range AMD dominates, i would go for a Gigabyte 690G board with a 4400 or 5000 X2, it performs much better than the current one you have selected. Should leave you some room for a better graphics card cause the 2600Pro is a terrible card, something like a X1950Pro or X1950XT if you can still find would be way better, even a 7900GT/S.

I get a free copy of Windows from my University so I don't need an OS.

Even with a nicer motherboard if he dont overclock the AMD rig will destroy it. Plus the 2160 is much better at overclocking than 2140. Even if he wants to overclock, AMD rig can overclock to 3.0ghz. I will go with what rwpritchett and if u have more room get an 8800 gts 320mb. Remember theirs shipping and taxes thou.

Intel ftw if ya wanna overclock. Amd if ya don't. As others suggested, a 5200+ is the bang for your buck if you don't overclock. However if you are planning to upgrade every year or so, Intel would probably be a better choice since the Amd's AM2 socket is kinda outdated. Your pick but here's my suggestion: 5200+, 8800GTS 320mb, some decent motherboard (since you're not gonna overclock), 450-550watt PSU, some decent case, and 2gigs dual channel ram of the popular brands (doesn't really matter).

tuskon, the rig rwpritchett will be cheaper and better for games because of the better graphic cards.

Ok. Here's what I'm leaning towards.

AMD Athlon 64 X2 5200+ $125
GIGABYTE GA-MA69GM-S2H Motherboard $80
COOLER MASTER Hyper TX2 CPU Cooler $30
SAPPHIRE Radeon X1950PRO 256MB $135
A-DATA (2 x 1GB) DDR2 800 (PC2 6400) $69
FSP Group (Fortron Source) 500W Power Supply $60
Seagate Barracuda 160GB 7200 RPM Hard Drive $54
COOLER MASTER Centurion 5 Computer Case $50
Sony NEC Optiarc 18X DVD±R DVD Burner $31
Total $634

I really don't use huge amounts of HD space so I skimped a little on the HD. 160gb is way more than enough for me. How's the rest of it look? I'm pretty close to pulling the trigger on this if no one points out any problems to me.