I've had success with Foxconn NF motherboards but also had a few problems - memory and PCIe slots specifically.
That mobo design has been out over 2 years. I think your best 'bang for the buck' when you decide to upgrade would be an AMD 790FX.
You didn't mention whether you use XP or Vista. DX10 in Vista will give you a good boost in Crysis (not really a good measuring stick for you, anyway).
If you add a single HD 3870 to the 790fx this will give you an idea of where you stand - - - > >
http://www.anandtech.com/video/showdoc.aspx?i=3232&p=3
Impressive @ 19x12 and 25x16 - - and the following page for 3 x HD3870 on the 790fx showed 406w at the wall ...