Really depends on your play style. You will lean to one particular role based on what style you play. And now that they have more options in leaders and controllers, you can find basically any kind of power source that fits your fancy.
For me, I prefer certain classes for certain roles (i.e. I prefer a warlord over a cleric). My favorite is actually hybrid because then I get to redefine my PC. I currently play a hafling rogue/warlord hybrid that I am having fun with.