I have 5:
2 Keeper Leagues ($)
1 Dynasty League ($)
1 Work League ($)
1 Public Yahoo League (I need something to mess with while I wait for the drafts in my real leagues)
I'll probably drop one of the keeper leagues next season since I was mainly rebuilding it for the commish. Now that I have A. Green/Alexander/Ward he shouldn't have any trouble finding a new owner. But I wanted to take it for a test drive before letting it go.
I love the dynasty league, it's by far my favorite league. If I do sell one of my keeper leagues next year I'll either add a dynasty league or auction league (been wanting to try that).