Another Help with Final System Build!

Good Morning,
After reading through the forums for a while, I think im finally ready to purchase a PC in the next week or two. And like everyone else, just wanted some final opinions. I have a newer Dell 2007FP that maxs out at 1600x1200 which is what I tend to play everything at. I might get another monitor in a few months, I havent decided. My computer is over 3 years old for reference.

I'm not sure if im going to do any overclocking, but it could be an option if I need to or want too. I only plan on running just one video card. For Gaming I tend to play MMO's, RTS, RPGs, and some first person shooters. I dont need to have my FPS set to max high for everything in case that matters. I do really enjoy a quiet machine when im surfing the net, emails, etc.

I already have Ultimate Vista 64bit and the Antec 900 case. Im looking to spend about $1,000 for the rest.

Case: Antec 900 which i already own.
Motherboard: Asus P5Q Pro
CPU: Wolfdale E8500
RAM: OCZ Platinum 4GB (2 x 2GB) DDR2 1066
PSU: Corsair CMPSU-620HX 620W
Harddrive: WD Caviar Black WD7501AALS 750GB 7200 RPM 32MB Cache SATA 3.0Gb
Video Card: Visiontek ATI HD4870
DVD Burner: SAMSUNG Black DVD+R SATA DVD Burner with LightScribe
2 Additional 120mm Fans for case if needed: Scythe S-Flex SFF21E

Total: 1015.92 including 2 mail-in-rebates for $40.00

The only thing that im concerned with is RAM. I have read that 1066 or 800 really wont make a difference with what I can tell with this setup, but im not sure if thats true or not. Thank you so much for your help and advice!

2 things i'd change.
Use this memory- DDR2 800 1.8v Mushkin $69 after rebate
http://www.newegg.com/Product/Prod [...] 6820146731
Use this hard drive (that's a lot of money for an extra 110GB) WD 640 GB $85
http://www.newegg.com/Product/Prod [...] 6822136218
for an extra $30 you could get 2 and just use one for storage, but 640 GB should be fine.

If modular or not doesn't bother you for the PSU, I would buy the Corsair 650TX, or even the 750TX, since they are both cheaper, and better wattage.

The 32 cache does make a difference, but not much of one, certainly not worth the $$. Here's a link of reviews on 320GB drives, some info should carry over to the 640. Pretty small difference from larger cache.
http://www.hardwaresecrets.com/article/603
The 610w PC Power and Cooling PSU is a great PSU at a great price. Save you some $$$ over the 620w.

If you plan on overclocking then I'd suggest you drop the E8500 and get the E5200 for $100 less (it's an 800FSB 45nm CPU with a x12.5 multiplier) or a Q6600. You have an almost guaranteed 3.5 Ghz OC with pretty good chances of hitting 4 Ghz after some tweaking with the E5200.

I would suggest spend some of the savings on a decent CPU Cooler like the Xigmatek HDT-S1283 or the Zerotherm Nirvana and keep the rest as beer money.

Thanks for that! Decided im probally not going to OC and just stick with the E8500 and work that avenue. Just easier.