Woops Knew i forgot something:
E6300 (2 Ghz)
Gigabyte GA 945P-S3
2x 512 Corsair TwinXMS2 5400 (675)
Palit 7600 gs (530, 550)
Coolermaster Hyper TX
and psu is just a 15 quid 2 fan psu 500 w.
What are your temps? I would expect that spec to run fine with the fans you list. Do you plan to try to clock faster?