Everybody knows that the best relationships are the ones fraught with drama. While kind, loving relationships are all well and good, they don't make for great entertainment. If you really want to get people interested and play their heartstrings like a fiddle, you need to set up a fantastic friendship and then pull it apart. Give people a reason to care before you introduce a conflict, and you'll hook them to an amazing extent.

In the world of 'X-Men' movies and comic books, the rocky relationship between Professor Charles Xavier and Magneto is the centerpiece of the mutant soap opera. One-time friends and battle allies, their difference of opinion on non-powered humans drove a permanent wedge between them. Sure it may be tragic, but the fight scenes look impressive on the big screen. Fans are eagerly awaiting the release of June's 'X-Men: First Class,' (in theaters June 3) which examines how Xavier and Magneto met and what exactly led to their complicated love-hate relationship.

With that in mind, here's a look at five more of the best friends-turned-enemies in comics.