has a lot to do with what kind of sound your looking for. check this out:
http://www.dimarzio.com/audio/audio.html
I run:
Super 3 (Bridge)
Air Norton (Neck)
Evolution (Bridge) Air Norton (Neck)
Tone Zone (Bridge) PAF (Neck)
(I love the Air Norton in the Neck but a lot of people don't. They think it's too hot for a neck p/u)
You just need to find the sound your looking for. If you have only one instrument I would go for the widest range possible from the bridge to the neck. NEVER limit your self or you will become frustrated when you can't get the sound you want. It's hard to get every sound out of just one guitar. That's why you see some many artist changing insturments on stage. *
Evolution (Bridge) Air Norton (Neck) is my favorite combo very versitle from bright leads to smooth tone blues.

my 2¢
~R~