As a starting point (as most of don't have a swag of fins) what we are finding works well is a DOLPHIN style centre like the FCS Fluid Foils - 5-6" fin for 9-9'6 board or 7"+ fin for a 10'+board.
Or FUTURE PINS Performance is another really nice fin-
Blane's Thruster Side bites of choice are the Sunny sides-
If you are not riding in super juicy waves then throw in a pair of FCS FG-5's or FG-7's.
These fins have an inside foil (concave) and definitely make the board feel shorter.
Downside is that they can get a bit sketchy when hitting mach speed!
As Blane says it really boils down to your personal style & choice, but the above fins are good starting point.
Any one else found some good reliable set-ups?
Hope this helps!
Andrew.A