First the questions:

1. I'm concerned about my power supply being able to handle all this. I think it can, but looking for thoughts. It's a 500w with 2 12v rails at 17v. Here is the PS (it comes with the case I'm getting, but this is just so you can see it by itself):
http://www.newegg.com/Product/Prod [...] 6817371007

2. I'm undecided about what CPU to go with. Right now I'm looking at the Intel Core 2 Quad Q6600, as it's only $20 more than the Intel Core 2 Duo E8400. However, I'm not sure, and looking for input. Both OC well, I read.

Feel free to comment on any part of it tho!

Current build:

CPU(s):
http://www.newegg.com/Product/Prod [...] 6819115017

or alternatively

http://www.newegg.com/Product/Prod [...] 6819115037


MB:
http://www.newegg.com/Product/Prod [...] 6813128337

GPU:
http://www.newegg.com/Product/Prod [...] 6814130347

^ The extra cooling so I can OC it.

RAM:
http://www.newegg.com/Product/Prod [...] 6820146731

^Cheap, reviewed well, OCs well it seems.

Case/Power supply:
Antec Sonata III 500 Black 0.8mm cold rolled steel ATX Mid Tower Computer Case 500W Power Supply - Retail

CPU Cooler:
http://www.newegg.com/Product/Prod [...] 6835118019
^ too much for my chip(s)?

Thermal Paste:
http://www.newegg.com/Product/Prod [...] 6835100007

Parts I'm carrying over from an old computer: 1 Sata hd, 1 EIDE hd (storage), 2 optical drives, case fans

Cost: $789.89 + $31.79 shipping = $821.68 (- $50.00 rebates). That's right where I want to be. This is meant to be as close to $800 (or sub) as possible

Antec EA500W PSU gets a very good review from JonnyGuru.com. It will handle the new system easily.

Can't go wrong with either CPU choice. Either one will be an excellent choice.
I like the Mushkin RAM you picked - good choice.

The only problem you might have is that with 1 EIDE HD you'll only be able to carry forward 1 other EIDE/PATA device (of your 2 2 optical drives)
Most motherboards these days only support 2 PATA devices without adding in a PCI card.

ahhh, good catch on the EIDE's, didn't know that. Thanks!

Either cpu is a good choice. But if you decide on the quad, get the cheaper OEM seeing how your going with aftermarket cooling. BTW, that Zahlman is spendy for the job it does. We can find better for cheaper. And the motherboard you chose...well the new P43 and P45 boards are finally out now, they have the latest chipset and they overclock nicely not to mention that have features the P35 boards didn't offer. Also there is no bios and driver upgrading for these new boards seeing how they come updated.

http://www.frostytech.com/top5heatsinks.cfm <---Heatsink reviews. XIGMATEK is always rated #1 or #2 on these review sites.

http://www.newegg.com/Product/Prod [...] 6819115018 $199.99
Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Quad-Core Processor - OEM

http://www.newegg.com/Product/Prod [...] +P43%2fP45 <---P45 and P43 boards. They just came out recently.

http://www.newegg.com/Product/Prod [...] 6835233001 $24.99 ($14.99 after $10.00 Mail-In Rebate)
XIGMATEK HDT-S963 92mm Rifle CPU Cooler - Retail

or

http://www.newegg.com/Product/Prod [...] 6835233003 $36.99

http://www.newegg.com/Product/Prod [...] 6835233019 $6.99
XIGMATEK ACK-I7751 Retention Bracket - Retail

http://www.newegg.com/Product/Prod [...] 0&Tpk=mx-2 $6.99
ARCTIC COOLING MX-2 Thermal Compound - Retail

Thanks Why_Me! I switching my CPU cooler and thermal paste to what you recommended.

However, with this P43 MB, can I still use DDR2 800 RAM, as it isn't listed as a memory standard
http://www.newegg.com/Product/Prod [...] 6813128347

Yep! DD2 800 is the way to go. It supports DDR2 800 on up.

Thanks, you've not only helped my setup, but shaved off a few dollars too! Thanks for your help, I REALLY appreciate it!