I mean, I found a place for AMD's phenoms in my heart (took me a few months, I'll be honest on that...), however I'm still trying to find a place where I can recommend them without them falling short to intel.
The only thing the Q6600 lacks is the SSE4 instruction set, which helps mostly on video encoding, if you do it very little or not at all, then it's not worth stressing over it, it really is important for people who do video encoding as their primary use though. I'd say go for the Q6600 and the build you previously listed above as your best option, you'd just need a CPU cooler down the road when you decide to OC your CPU.
Crysis is a graphical behemoth (and to me also a fun game, I really enjoyed it), you shouldn't have to worry about performance to be CPU-bound, especially with a Q6600 (even though Crysis uses up to 2 cores I believe), it is more GPU-bound than anything.
Another possibility that I haven't seen being brought up here is CF HD 4850s, which should run you for about $320-340 and will give you a performance level only bested by the $550 HD 4870 X2.
ASUS P5Q Pro LGA 775 Intel P45 ATX Intel Motherboard - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131299
Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Quad-Core Processor - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115017
CORSAIR 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16820145184
Seagate ST3640323AS 640GB 7200 RPM 32MB Cache SATA 3.0Gb/s Hard Drive - OEM
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148335
(Two of these) SAPPHIRE 100245L Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102770
PC Power & Cooling S75QB 750W ATX12V / EPS12V SLI NVIDIA SLI Certified (Dual 8800 GTX and below) CrossFire Ready 80 PLUS Certified Active PFC Power Supply - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703009
Don't go SLI or use nvidia cards at the moment, they brought out some decent cards, but Ati pretty much shocked the world afterwards with their offerings, that's why everyone and their mom are getting Ati cards nowadays (myself included). About the screen, even though you might spend a little bit more, it is definitely a good idea to check out the screen in person because you can make sure it has no dead pixels and see what it looks and feels like before you drop any money on it, you should be paying a $20-40 or so mark up, but for the screen it's worth it.