Right now I'm using a kingston 32 gig 133x elite pro that I got for about 100 bucks. Doesn't have any issues capturing HD or high speed continuous shooting. I also have a 16 gig sandisk III I think. I'm very surprised/pleased with the kingston, honestly. After paying egregious prices for P2 cards, I feel like I'm in heaven.
HD record times are limited to 12 minutes. I've heard the 133x cards OCCASIONALLY fill up the buffer, but I've also heard they work great. 8GB card holds 24 minutes of footage (2 12 min. chunks). I have 8x 8GB Sandisk Extreme III's: