Check my sig. Currently using 2 150x 4gb SD cards (not SDHC). IMO this is the best setup.
It does support SDHC cards as well, but there isn't much point when they are slower and cost more.
Nikon D300 | Tamron 17-50mm f/2.8 | Nikkor AF-S 70-300mm VR | Nikkor AF 35mm f/2 D | SB-600 | Lowepro Voyager C | Lowepro Slingshot 300 AW
Nikkor AF 35mm f/2 D - Like New (FX compatible)
Nikkor AF-S 17-55 f/2.8
Nikkor AF-S 70-200 f/4 VRII
Tokina AF 11-16 f/2.8