Some of these are obviously better but

Completely biased and basic here

But I'd take either Absolute Obedience or Time Stop

Personally I think Mind Reading is the one Geass I'm totally into. I mean you can use it to read peoples minds and try to communicate with them through each other's minds. If that's not the Geass I wanted, then I don't know what it is.

Not on the list but I like Shamna's ability, maybe not the most practical but relatively powerful