Hi there,
Thought I'd chime in a little. Here's my experience, although it's a little bit on the hair splitting side.
Active pickups are tighter sounding than passive pickups. They compress the sound a lot. If you do a lot of fast-tight riffing like most trash/death metal do (think Mustaine and Hetfield), then active pickups are the way to go. Passive pickups however, has more dynamics. It's looser sounding, so it's more sensitive to the touch, especially your picking hand. This renders it suitable to guys/gals that like to play with dynamics in their guitar work.
This doesn't mean that passive pickups can't be tight sounding. It can, but there are some other factors to consider, like the type of pedals/amps you use and how you set them.
There are of course exception. David Gilmour uses (or maybe used?) EMG actives (with lots of switches and effects) and he plays some of the most soulful melodies around. Gilbert and Malmsteen can pick (and sound) very tight and accurate even though they use passives.
If I were you, and I play STRICTLY metal, I'd go EMG.
There you go, clear as mud.
~sentot