What do you think of this setup?

Intel Core i5 750 2,66Ghz Processor (Will overclock it to atleast 3,3Ghz)
G.Skill Eco 4GB DDR3 1333Mhz 7-7-7-21 Memory
Asus Rampage Maximus III Formula P55 Motherboard
2x XFX Radeon HD4890 in CrossfireX (Will overclock both of them aswell)
Samsung Spinpoint 320GB HDD for OS and stuff
Western Digital Green 1TB HDD for storage

This is what I'm getting.
I will be playing these games:
Call Of Duty 4: Modern Warfare @ 1920x1080, Max Setting, 4xAA

Call Of Duty: Modern Warfare 2 @ 1920x1080, Max Setting, 4xAA

Counter-Strike: Source @ 1920x1080, Max Setting, 8xAA

Crysis @ 1920x1080, Very High/Enthusiast, 4xAA

Far Cry 2 @ 1920x1080, Max Settings, 4xAA

Alot of other games, but those above are those i will play the most
I've read a review on the 4890's in CrossfireX, Link here.
The review show's some benchmark. Among others: Call Of Duty 4, Crysis and FarCry 2, which is some of the games I'll be playing. The benchmarks shows the games played at 1920x1200 which a tad larger then my monitors resolution, which is 1920x1080
I don't care to much for DirectX 11 and rarely buy new games so I wont go for a DX11 card of the same caliber as the 4890.
The benchmarks was done on a similar setup:
Core i7 920 @ 3,8Ghz
Gigabyte X58 Motherboard
Only 2 GB of DDR3 memory
The benchmarks showed that the 4890's in CrossfireX beats the GTX295 in Crysis at 1920x1200 with 4x Anti-Aliasing. That's why I'm getting the 2 cards, since they're cheaper and beats the GTX295 in several games.
What do you think about it?

i would make a few changes:

CPU: good

MOBO: a bit over priced, so might wanna get another one

RAM: great

GPU: i would get 1 5870...same price as the 2 4890s, possbily more (probs the same or +/- 5%) performance, support dx11, less power, and 1 card is always better than 2 as far as the amount of hassle.

HDD (OS): ? either get the 500 Gb version, or get an ssd

HDD: get the 1 tb version of the f3

thats about all i can recommend

I would recommend a mobo with USB 3.0 and SATA III like this one:
http://www.newegg.com/Product/Prod [...] 6813128423

Same price, but more "future-proof". Two PCI-e 2.0 lanes at x16, two at x8; you only need the first two for CF.

Also, do get the Samsung F3 like ares1214 mentioned, it's a much better HDD.
If you get the 2x 4890s, make sure you have a quality 800W+ PSU. If the 5870, 600W will do.