Best Pickups for Metal?

Any of the main manufactures will offer something that suits you, it's just a case of choosing.
Look at bands that play in the same register and see what they're playing. Find a tone that you like and copy what they're using... :)
 
I'm a big fan of the SH-5 Duncan Custom for metal. Have one and plan to get another for a different guitar. I spent two months or more researching and listening to various samples. The number of choices out there for pickup models is almost overwhelming at first. In the end I decided on the Custom. I haven't regretted the decision once and still love it a couple years later. Has the best artificial harmonics of any pickups I've used. I find they're better than my Jackson SLSMG with EMGs(was an 81 in the bridge when I got it but I've since swapped for the 85 in the bridge). Also, if you buy it from most music stores, you have typically a month in which to return it so you could even buy a few, try them in your gear and return the others.
 
It's important to consider what genre your'e playing as well as playing style when it comes to choosing a pick up. For example, I play black metal. I used to use an EMG 81 (Active of coarse) then switched to a seymour duncan black winter. I couldn't believe the sound difference and thats because the black winter is made to round out the sound of trem picking which is essential for that genre. If you'll be playing in drop A#, i'd suggest checking out some bareknuckles.
 
First of all what kind are wood of you guitar body? For example, one kind of pickups work great at alder body, but not work fine with mahogany.