Sub $500 gaming system (key parts only)

APPROXIMATE PURCHASE DATE: Like it to be within a week, even this weekend.

BUDGET RANGE: US $500

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: gaming, movies, internet streaming movies, surfing, productivity

PARTS NOT REQUIRED: Technically, I don't need a monitor, but I've included one because it's so cheap. No keyboard, speakers, DVD drives, case (using Antec P180 quiet case), OS (may upgrade in future to Win7. Using XP now and yes I know about memory cap in XP), power supply. Currently using a Antec Phantom 500 500W ATX12V and love it. I picked some parts with this in mind. It *should* be sufficient for my build.

PREFERRED WEBSITE(S) FOR PARTS: newegg.com unless a really compelling reason is suggested for another. I've been buying from them for years.

PARTS PREFERENCES: Would like to stay with Phenom AMD CPU, XFX Nvidia graphics, Gigabyte MB, WD Green drives. 2 cores on CPU is as expensive as I'm willing to go.

OVERCLOCKING: Yes SLI OR CROSSFIRE: Absolutely No

MONITOR RESOLUTION: 1920 x 1080 or there about. (monitor and graphics both support)

ADDITIONAL COMMENTS: Looking to make a quieter more energy efficient machine. I know I've really blown it with a couple of the parts I've picked, though. If you can suggest improvements, great.

I had parts picked out for a sub 500 machine, then saw a 24" monitor cheap, and did a little reading about them and picked the one I have below. My mouse is dying, so I threw in a wired gaming mouse, too. As of tonight, the parts without shipping are 751.92. If I went over 800 bucks, I'd freak. It's already 250 more than I really wanted to spend. That monitor is really got me happy, though, and even if I do NOT buy anything else, I'll be buying a monitor.

Upgrading from a machine that's almost four years old (December 2005. Still have the newegg receipt), and I still play most games reasonably well (Oblivion, Fallout 3, any MMO I've tried). Still, this will be a major upgrade for me even using budget parts. The parts I picked have lasted VERY well over this time. I'm hoping for at least 3 years out of what I get now.

Any advice on going cheaper, better memory, better AMD CPU, better graphics (cheaper if possible), or really any better, but similarly priced parts would be appreciated. These parts should all be compatible.

In the past, I had extensive knowledge building machines and have built many, working for a small company, then doing it myself, but I've been out of it for a few years now. If I made a mistake with any of this, please point it out.

Parts List:

ViewSonic X Series VX2433wm Black 23.6" 2ms(GTG); 5ms HDMI Full 1080P Widescreen
(currently have a 19" Viewsonic LCD)

WDCaviar Green WD7500AADS 750GB 32MB Cache SATA 3.0Gb/s
currently using an assortment of drives in raid for about 800GB of storage.

GIGABYTE GA-MA770T-UD3P AM3 AMD 770 ATX AMD MB
currently using an ASUS A8N-SLI Premium 939 NVIDIA nForce4 SLI ATX AMD

XFX PVT98GYDLH GeForce 9800 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16
currently using an Nvidia 7800GT

AMD Phenom II X2 545 Callisto 3.0GHz 2 x 512KB L2 Cache 6MB L3 Cache Socket AM3
currently using AMD Athlon 64 X2 dual core

Crucial 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Dual Channel Kit Desktop Memory Model CT2KIT25664BA1339

Logitech G5 7 Buttons Tilt Wheel USB Wired Laser 2000 dpi Mouse
Currently using a G7 wireless. Would like to go back wired.

I'm a Linux user as well. ATI decided to not support older hardware with their latest drivers on the latest Ubuntu, and I would rather not buy another ATI video card at this time. Nvidia's are supported just fine, though.

The Green drives are purchased for power consumption in mind, as well as dB. They're better than what I have. I realize this Black drives are faster, but noisier, and more hungry. If you can recommend other low power, low noise drives, great!

I'm not really interested in a blazing system. Everything I have listed is a major upgrade from what I have, and I already play everything I want to. All I'm looking for is improvement on a tight budget. If you can tighten the budget, and improve performance, give me the suggestion even if they contradict my preferred parts.

That said, I intentionally limited things so responses would be faster. The broader my desires, the more items there will be to fill them, and the harder it will be to narrow my decision. I'm already pretty set in my ways and who I like to support from having worked with computers since the mid 80s (yes, I know ATI is owned by AMD these days). I'd almost be willing to switch to an Intel, but I haven't owned one in over a decade. It would feel funny.

Anyway, if you can't help, thanks for reading anyway. If you can help out, it's much appreciated.