I roll with humbuckers, real bright humbuckers most of the time. I like the sound of fat warm humbuckers when it comes to playing soulful blues, but I need (or more like, prefer) string definition when it comes to playing hard rock stuff. I like humbuckers that are really bright, even for neck pickups. That's how I stopped liking Gibsons and became a PRS guy. For neck, I like to be able to stray into quasi-single-coil territory, but can still do humbucker stuff with the tone rolled back. For bridge, I like something bite-y, a bit like those AC/DC or 80's glam metal sound. I like the middle position as well, especially with my D Activators. They're almost strat-quacky sounding, really cool for Clapton or Mayer blues, especially when you're playing with your fingers. Oh and it can also get very funky.
Single-coils work for me too, I love a good ole' strat neck pickup, and that's the only single-coil i've ever played, all these strats that I put my hands on, has the selector pointing upwards only. Occasionally I like P90s, but I don't like the hum.