The quintessental combination is, of course, Robilar's Gambit + Karmic Strike, get as many AoO's as you can get, and a weapon that increases your hit points when you do damage.
Someone looks like they are going to hit you, You get an AoO.
Someone Hits you, you get an AoO.
The two combined lower your AC by 8, and you take +4 damage, but if your weapon gives you HPs, it won't really matter, now will it?