Well, for starters maybe you'd like to name the bands u'd like to emulate, your current gear, budget and your guitar model so we can help you to further 'customize; your pickup choice. Also, you need to consider whether you want to change all, 1 or 2 of your pickups.
Off the hook, i'd recommend the Tesla Plasma III humbucker available at SV, its able to handle the heavy stuff well, with clarity for those solos. Or if you've tried it and its not to your taste, you can try Dimarzios like the D-Sonic or the X2N, both of which are really hot. If you think passive pickups just don't cut it where your metal tone is concerned, go for EMGs or Lace Sensors. I'm not a fan of active pickups, thus i'll let someone more versed in that area advice you.
It is of utmost importance that you test out the pickup b4 slapping into your guitar. Do go around trying the different pickups and see what's best for you. Cheerz!