I prefer CompactFlash cards to SD, despite the bulk, for speed and durability. (Also, I shoot with big cameras that take big cards.) SD card version 4.0 fixes the speed issue, with transfer speeds of up to 300MB a second.
It has a new pin for high speed data transfer, which is why it's nearly three times faster than current top end of 104MB a second. But it's the same size as current SD cards, and it'll be backward compatible with current card readers. The spec for SD card 4.0's supposed to be done this spring, though there's no telling how long it'll take to actually see these on shelves. Until then, CF card it is. [Tech On Image via Tc7/Flickr]