More and more I've come to the conclusion that the best possible plot generator for a campaign is fully fleshed out non-player characters. Knowing who the major players are and what their relationships are to each other informs the next stop of the process which is plot generation.
The traditional method of developing characters is to fully flesh out everything before hand. This requires a great deal of work by the GM, and in my view it's boring. I like "discovering" relationships just as much as players do (probably more). In other words I'm more of a "connect the dots" kind of guy. To help out with this method of character generation I created a way of setting up relationships between NPCs by using a deck of poker cards and playing a hand of Texas Hold 'Em with yourself.