Questions on a new computer build (cooling? PSU? 2.5 – 3.5 adaptor? Stupidity?)

So here’s the order (all prices/links from NewEgg): [ul]
[li]Antec P183 Black Aluminum ATX Mid Tower Case – $129.99[/li][li]CORSAIR 850TX 850W ATX12V 2.2 / EPS12V 2.91 Active PFC Power Supply – $139.99[/li][li]ASUS P6T Motherboard – $239.99[/li][li]Intel Core i7-920 Bloomfield 2.66GHz Quad-Core - Retail – $288.99[/li][li]2 x GIGABYTE HD 5770 (Juniper XT) 1GB 128-bit GDDR5($165 each) – $329.98[/li][li]G.SKILL 6GB (3 x 2GB) DDR3 SDRAM DDR3 1600 (PC3 12800) – $149.99[/li][li]Crucial 128GB SATA II MLC Internal Solid state disk (SSD) – $429.00[/li][li]Western Digital Caviar Black 500GB 7200 RPM SATA – $69.99[/li][li]LG Blu-ray Burner – $199.00[/li][li]Total cost: $1976.92[/ul][/li]
First, feel free to critique the choices and whatnot or offer any opinion whatsoever. Of course, please point out if I did anything stupid like leave something out (Win 7 from another source; existing mouse and keyboard to be repurposed), have a glaring incompatibility, or anything. Though not its main use (mundane Office work), its main test will be in shooting zombies and editing home HD movies. Since its daily use is in the office, I won’t be overclocking in order to avoid any stability issues.

One thing that’s definitely missing is supplemental cooling. I’ve never run a Crossfire setup (notice there are 2 5770s in there), so I imagine that I’ll want some additional airflow. Again, I won’t be overclocking, so that heat build-up won’t be something to contend with, but I’d be surprised if stock fans are sufficient. I’ve ordered nothing so far in this regard — the CPU fan is stock retail, as are the cards. Just an additional slot fan? Just a couple more case fans to ensure movement? Given threads complaining about room over the board, I’m not sure which heat sinks (if necessary) will work — any suggestions?

I went to a few different power supply calculators (e.g., Outervision, NewEgg) and got widely different numbers. I went with the higher of the recommendations, but thought to ask about it — again, lack of X-fire experience. I’d hope that 850W will be enough, but want to check that it’s not ridiculous overkill.

2.5 – 3.5 adaptor
I’m pretty stoked to be going with the SSD. But it’s 2.5", so I assume I’ll need some sort of adaptor to set it in the case. I’ve seen a few, but they’re a bit specialized for older PATA setups. Does that matter?

Video editing
Also from the no experience department. We have a new Canon HD camcorder (thanks bro!), our only source of video input. Simple splicing and shuffling, nothing fancy. From what little I’ve been able to find, the work should be split between the CPU and the graphics cards. Or should I also be looking at a small Workstation card as well?

Repurpose existing box to the den
I’m currently sitting behind an AMD 4800/ATI 4850/2GB/Win XP setup. After the change I’d like to move this machine to the den and use it to watch Hulu, Youtube, surf, etc. on the television. I ordered a DVI to HDMI cable — is there any way to get sound to go along the HDMI as well? Is there anything else I’ll need? Would I be better off swapping it out, sending it to my brother, and putting in a different card? If it makes a difference, it’s going to a 57" HD set.

Lastly, any game recommendations — something that I can load on the current system before the build to check out the difference? I’m a bit partial to FPS e.g., (L4D, Bioshock, HL, Fallout), but will have at anything if the eye candy is sufficient. I’ve yet to play Crysis, but it’s a couple years old now — or is it still a standard test? But it’s the holiday season, so I assume there’s something new out there.