Would it be enough to power a i7 930 OC, either 2 GTX 460's or 2 5850's OC'd, 3 Caviar black HDD, X-Fi Titanium, Asus P6X58D-E, 3 120mm fans, 1 140 mm fan, and 6 GB Dominator 1600 OC? Overclocking will be around 10-20% for the different components.
and is this a PSU i should get or is there something of better value but similar quality? or do i need to move up to an 850w?
You certainly don't need an 850w unit. I think you barely need a 750W one. So if you want modular, go for the 650W editions of the XFX or Corsair HX. The only reason to go more powerful is to keep the system for a very long time or the PSU for a second build.
If you have a case that mounts the PSU in the bottom then the necessity for a modular PSU is reduced considerably compared to a top mounted PSU case.