BTW I just wanted to add in that this will be my first build.
Thermaltake Shark Full Tower Case (Black) Love this case
Asus MsN32-SLI Deluxe Wireless Motherboard (give me ideas on a better Asus Motherboard)
AMD Athlon 64 X2 4200+ Windsor 2000MHz CPU
PC Power & Cooling 510 SLI Power Supply
4GB XMS 240 Pin DDR2 800-6400 Ram
Western Digital 500 GB Sata II Internal HD
EVGA Geforce 7900GT KO SuperClocked Video Card
Plextor PX-230A Cd Burner
Sony DDU 1615 IDE CD-Dvd Rom Drive
Klipsch 2.1 Speakers
Questions:
How good is the sound on this Motherboard? Do I need to buy a sound card to play games.
Do you think I'll need extra cooling with this setup or will the stock setup suffice?
Any and all input will be appreciated.
Your choices are fine for the most part. There's a couple of questions you need to ask yourself though.
Do I plan to get another 7900gt at some point and run an SLI config?
Yes: then keep the motherboard
NO: downgrade to a non sli nforce 5 chipset board from Asus
Do I really need 4GB of RAM?
Yes: if you do tons of multi-tasking eg. video encoding, while gaming at the same time and/or I use a 64bit operating system. Then MAYBE you need 4GB or RAM, but you will have to use msconfig to change the BOOT.ini advanced options to set the ceiling for RAM higher, to utilize it under 32 bit WinXP.
No: This is probably the answer you will choose if you are building your computer primarily for gaming. Win32 has a 2GB per process limit anyway and running four banks of RAM will actually increase latency, degrading overall performance.
Am I going to be overclocking my computer?
Yes: Then keep your PCP&C power supply and get a zalman (or some other high quality) pure copper aftermarket heatsink and fan.
No (or only a light to moderate overclock): Then ditch the PCP&C power supply and get something like the Antec true power II 550 for about $130 less; it's stable, reliable and more than adequate for your current system, or even get a Tagan 530 watt for just around $110. PCP&C makes by far the best power supplies out there, but they are just complete overkill unless you are going to be doing some heavy duty overclocking, 24/7 high load computing, or just want the baddest a$$ power supply money can buy. As for cooling the stock heatsink and fan will be fine unless you really plan to push your silicon.
other thoughts
instead of a plextor CD-writer there are some excellent DVD-burners for around $40, the BenQ 1650, NEC 4550 come to mind
Onboard sound has gotten much better in terms of quality and overhead, but onboard sound uses the CPU, and you will take a framerate hit in games when using onboard sound. I don't know much about Asus's onboard sound for that motherboard, but an X-fi would be complete overkill for a 2.1 speaker setup (even though it's high quality Klipsch). I'd recommend an Audigy 2 ZS; you'll get good sound quality and save yourself a handful of cash.