looking into cost wise if you buy wisely you can get a decent deal on that build however my build was only a few hundred more (minus the cost of processor) but i suggest getting a 990x if you can over a sandybridge.
my build cost 3800 and i got
i7 990x hex core
24g corsair XMS3 ram
asus sabertooth MOBO
Radeon HD 6990
1000w Modular PSU (Corsair)
NZXT Phantom tower
2x 1tb 7200 rpm 64mb cache Raid 0 drives
2x 2tb 6400 rpm 32mb cache Raid 1 Drives (for storage)
and just a regular LG dvd rw read/writer.
overall if you shop around you can get good deals and save money i got a little impatient coulda saved more but still got good deals on most parts.
in the end im running BF3 at 190 FPS average on ultra and i plan on putting another 6990 in, and ive spent almost half of what i would going with alienware and getting a shittier build