First time build

I was recently gifted a CPU and motherboard which, while not top of the line, are certainly better than what I currently have. I figure it's a good excuse to upgrade the entire system and since I've never built my own computer before, I would like a little advice on pulling it all together.

APPROXIMATE PURCHASE DATE: 1-3 weeks.

BUDGET RANGE: Approximately $800 after rebates (but including shipping). My long-term goal is to eventually replace the CPU/motherboard, so I don't want to invest heavily in items with a limited tech lifespan, but am willing to spend a little extra on items I'll be able to move along to future builds.

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Gaming (primarily World of Warcraft and single-player games. I'm not much into the super-intense multiplayer games), web browsing, word processing.

PARTS NOT REQUIRED: I was gifted an Intel E6600 (2.4 GHz dual core, 4M L2, 1066 MHz FSB) CPU along with a Gigabyte GA-EP45-DS4P (P45) motherboard. Neither are what I'd choose today, but hey, they're free! I also have a Soundblaster Audigy 4, keyboard, mouse and Envision 22" monitor.

PREFERRED WEBSITE(S) FOR PARTS: Newegg and Amazon.com

PARTS PREFERENCES: None, but I don't want shoddy parts.

OVERCLOCKING: Unless I get a lot of "this is a bad CPU to overclock" responses, I'll give it a try. I can't afford to overclock too aggressively, however.

SLI OR CROSSFIRE: Not until I upgrade the CPU/motherboard.

MONITOR RESOLUTION: 1680x1050

PROPOSED PARTS LIST: Based on various sources on these boards and outside reviews, I've come up with what I hope is a fairly reasonable parts list. That said, I don't know whether they'll all play nicely together and whether there might be better options out there (either better-priced or better-quality are both welcome).

Case: I'd originally planned on going with an Antec P182 (~$150 + $30-40 for additional fans) due to its solid construction, removable filters (I live in a 100+ year old house) and good air handling. Unfortunately, the GPU I'd planned on scavenging just burned out, so I'm going to have to cut some corners here to stay in budget. I'm currently leaning towards the Antec 300 Illusion (~$65) as a compromise.

CPU Cooler: Sunbeamtech Core-Contact Freezer ($25)

Memory: I have two options that I'm considering:
1) G.Skill 2 x 2GB DDR2 800 MHz (4-4-4-12) ($100)
2) G.Skill 2 x 2GB DDR2 1100 MHz (5-5-5-15) ($105)
I don't actually know which is better - the faster speed (to go with overclocking?) or the better timings, so a recommendation would be greatly appreciated.

Graphics card: Again, two options that I don't know which would be better:
1) XFX Radeon HD 5770 (Juniper XT) 1 GB 128-bit, DirectX 11 ($180)
2) XFX Radeon HD 48901 GB 128-bit, DirectX 10 ($190)

Hard drive: Western Digital Caviar Black 1 TB (7200 RPM) ($100). I may cut back to the 750 GB version to save $20.

Optical drive: Samsung Lightscribe SATA II DVD-R ($30)

Power supply: Again, lots of options. 650W should be sufficient for my current usage, but I'd like to have extra headroom in case I go SLI/XFire down the road. I'm also not certain just how useful a modular PSU would be. Currently considered options (I've stuck to Corsair for high reliability/reasonable cost):
1) Corsair 750TX ($90). This seems like the best value to me currently.
2) Corsair 850TX ($120). More juice, but more money.
3) Corsair 650HX ($120). Modular, slightly higher rated PSU, but less power.
4) Corsair 750HX ($140). Modular, best efficiency of the bunch.

Operating System: Windows 7 Home Premium ($110, going with retail version since it's essentially the same price)

Other: APC Back-UPS RS 800VA/540W ($125) APC's calculator says this should be enough for even an i7, but I don't know enough about UPS's to know for certain. Again, help/recommendations would be useful.

Another potential purchase would be a fan controller (my motherboard doesn't support fan control and the Antec's fans all require removing the case to change), but I'm not certain it's something I truly need.


Thanks in advance for any help you can help!