I can see in the manual that they recommend Class 4 SD card, but there are cheap SDHC Class 10 cards on Ebay from Hong Kong.

Can you guys recommend a SD card which has no problem with speed and duration of the video during recording?

There really is no need to go for a class 10 card with the Gopro's... We just use the cheapy ebay ones and have never had a problem.. (and we sell lots of them)

If you do decide to go the class 10 though - I use one of the Class 10 - 32gb 'Team' brand cards in my Canon 550D and it works just as well as the Sandisk Extreme. I've compared both and the difference is very very small, and the Team is half the price...

Thanks guys. I've ordered Kingston 32Gb Class 6 for 69$ from Australian reseller.