I have been lazy and just left mine on the "0" and "9" keys, though I will likely have a hotkey set up when i ding 80 soon and start my heroics, but up to 80 I don't find myself needing too mnay action bar spells for my hunters and they are comfortable there.

I actually also have my Warlocks life tap on the same key as the hunters Viper aspect just for simplicities sake, not the most efficient set up but it works for me because i'm a bit absent minded!