Build Spec Review

Hi Guys,

Can you cast your eyes over a build spec I have been putting together?

Graphics: Radeon HD 7990 x2 £700
Motherboard: Gigabyte GA-990FXA-UD7 £160
CPU: AMD FX-8320 £115
RAM: Corsair CMZ16GX3M2A1866C9 Vengeance £100
PSU: G1600-MA-EU £190
Case: Aerocool Bx-500 Black Edition Midi Tower Case £65
Hard Disk: Seagate Barracuda 2TB 7200RPM x3 £160
Cooling: Arctic Fans £40
------
£1530

In particular whether or not it's worth getting, 2x 7970x2's or more 7970's for the same price (not sure why this would make a difference...) or looking at the 290 although so far they seem to have pretty poor reviews in the cracking world

-- EDIT --

Just Realised that the 7970x2 is essentially the 7990.... my bad....

Thanks in advance of your awesomeness