Best Villain/Hero team up ?

If a villain and a hero were to team up who would be the best two ?

Shazam and Adam

I always liked when Xavier and Magneto would team up.

Ikari and Daredevil - Written by Mark Waid.

Daredevil and Kingpin

Batman, Lex, and Ras al Ghul.

Cassandra Cain and Harley Quinn. (Honestly I think this would be hilarious)

New 52 Batman and Deathstroke would be awesomeberries to the extreme.

1. Batman and Lex Luthor
2. Batman and Ra's al Ghul
3. Batman and Deathstroke
4. Batman and Gotham City Sirens
5. Batman and Bane

Grundy and Hulk

Optimus Prime and Megatron