[shuttertalk]

Good question Icburns... I personally use Sandisk but looked up the SD association page and they recommend class 4-6 speed for HD to Full HD recording, and class 10 for Full HD recording IF your device supports a high speed bus.

https://www.sdcard.org/consumers/speed/speed_class/

Then again though I hear the speeds differ between manufacturers so a class 10 from one might not be the same as a class 10 from another...