Should be more than enough, depends if its continuous recording though. the go pro battery is likely to go flat before you use that up. I use a kingston 16gb class 6
its fine. Remember there will be a lot of pausing whilst still using battery, also its easier to edit smaller clips.
EDIT - Just got this of the go pro website
With a single battery, you will get approximately 2.5 hours of continuous video recording time in mild and warmer temperatures. Cold temps will reduce run times somewhat, however the HD HERO camera helps to minimize this by transferring the normal heat generated during operation towards the battery.
Recording time will vary according to the resolution setting used and the card capacity. Here are the average recording storage times for a 32GB SD card: 1080p (30 fps): 4h 21m 960p (30 fps): 5h 26m 720p (60 fps): 4h 21 720p (30 fps): 8h 09m WVGA (60 fps): 8h 09m