Mine would be none of the ones given in the poll, but live betting.

Not all sportsbook include live betting because I guess it's a bit different from normal betting...
I don't bet often on sports but when I do I like to be after seeing by myself how the players are acting, how is the mood, how they're behaving...
Live betting is great because you can bet on what you know for sure (teams results, location...) and on what you feel! On your understanding of the current game.

So I really like live betting!