Please suggest a good MOBO (and other parts) for my first build

so this is my first ever build and i have been non stop researching parts that i want for my ideal build. basically want a single gpu (dont plan on running SLI) machine that can run today's game in full settings at high res and run windows xp 32 bit fast, and fast web surfing

I am going for a total budget of $800 max
So far, I have finally decided on a CPU and a GPU:

AMD Phenom II X4 940 Deneb 3.0GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM2+ 125W Quad-Core Black Edition Processor
http://www.newegg.com/Product/Prod [...] 6819103471

and

EVGA 896-P3-1255-AR GeForce GTX 260 Core 216 896MB 448-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card
http://www.newegg.com/Product/Prod [...] 6814130434

So my problem is I cant figure out the rest...I really need help in selecting a mobo. I seriously am going nuts to find a mobo that fits the budget and utilizies the GPU and CPU i have selected well.

Also need to figure out and would really appreciate if you could suggest:

RAM (i think max speed with this CPU is 1066)

PSU ( no idea on which PSU will suit the power needs of all components)

CASE (i would like a mid tower size but not sure if the GPU and other components can fit into a mid tower with out blocking
out other ports on the MOBO)

CPU COOLING, COOLING PASTE, and CASE FANS - again little knowledge on how best to select cooling solutions

so again would like to stay under budget of $800. thanks guy, please help me out if ya can

If you want to cut the price down some in this build, switch to the Pony gtx 260. It's a good card, and easy to o/c. Otherwise this is a solid build. One more thing, ditch the XP if you plan on gaming. It only reads 3 gigs of memory, it doesn't utilize DX10 and it's all around a cooked o/s.

http://www.newegg.com/Product/Prod [...] 6811129042 $54.95
Antec Three Hundred Black Steel ATX Mid Tower Computer Case - Retail

http://www.zipzoomfly.com/jsp/Prod [...] e=10009795 $74.99 ($49.99 after MIR) Free Shipping
OCZ OCZ550FTY 550W Active Power Supply Retail

http://www.newegg.com/Product/Prod [...] 6813128387 $109.99
GIGABYTE GA-MA790X-UD4P AM3/AM2+/AM2 AMD 790X ATX AMD Motherboard - Retail

http://www.newegg.com/Product/Prod [...] 6819103471 $189.99 Free Shipping*
AMD Phenom II X4 940 Deneb 3.0GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM2+ 125W Quad-Core Black Edition Processor - Retail

http://www.newegg.com/Product/Prod [...] 6835207006 $29.99 ($19.99 after $10.00 Mail-In Rebate)
Sunbeam CR-CCTF92-4 92mm Core-Contact Freezer CPU Cooler W/TX-2 - Retail

http://www.newegg.com/Product/Prod [...] 6814130433 $194.99 ($169.99 after $25.00 Mail-In Rebate) Free Shipping*
EVGA 896-P3-1257-AR GeForce GTX 260 Core 216 Superclocked Edition 896MB 448-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Retail
Free Call of Duty – World at War w/ purchase, limited offer

http://www.newegg.com/Product/Prod [...] 6820231166 $54.99 Free Shipping*
G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory - Retail

http://www.newegg.com/Product/Prod [...] 6822136319 $74.99 Free Shipping*
Western Digital Caviar Black WD6401AALS 640GB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive - OEM

http://www.newegg.com/Product/Prod [...] 6827136152 $23.99
LG Black 22X (CAV) DVD+R 8X DVD+RW 16X DVD+R DL 22X (CAV) DVD-R 6X DVD-RW 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM 2MB Cache SATA 22X DVD±R DVD Burner - OEM

Total: $808.87 | $743.87 w/mail in rebates

http://technet.microsoft.com/en-us [...] ID=mscomsc <--- Save yourself some money on an o/s until March 2010 and dl the 64 bit version of Windows 7

http://www.newegg.com/Product/Prod [...] 6817341022 <--- more pics, specs and customer reviews of the psu in this build

Nice +1 for the changes

being that I am running an AMD2+ chip arent there speed limitations when it comes to RAM? Isnt 800 the fastest speed I can run in dual-channel mode?