Hmmmmm, certainly food for thought here.
As I said, my first thought was to simply go with what Tim suggested but in a way, the Miracle Man concerns me. It has the power I need without a doubt and is certainly articulate enough but the clips are very tight when recorded with a mahogany guitar so it may be too harsh when paired with Alder and Maple. The lack of a bit of variety I could cope with as 99% of the times it's going to be using a lot of distortion.
I think that if I have a concern about the Holy Diver it's because I have only ever really had ceramic pups before so I know they provide the cut and articulation I want. An Alnico V pup is more of a step into the dark for me. I had a Super Distortion in a Strat once and that was a great pickup and so was the Cold Sweat I had in my last guitar. Both pickups may have been ceramic but I loved the fact that they retained quite a rich and organic tone as well as having that cutting edge. I guess what I want is something like that but with a bit more power as well for the extra gain I can use these days. I know the Alnico V should have the quality of tone but I've never really associated them with the other qualities I'm looking for, though I'm happy to accept that I might be wrong. I'm hardly an authority! I know Antag has ample experience so if he's sure the Holy Diver will cut it, then I may well go that direction. Is the Holy Diver a bit like a Tone Zone as whenever I look at DiMarzio pups, I tend to be drawn to that, despite it being Alnico V?
If a ceramic would be better, the Painkiller seems like it offers the best compromise but as nobody else has picked up on that I may well be wrong. I'd be interested in not only hearing what you think would be best, but more importantly, why you think it would be best.
It may be worth pointing out that while a play a 'Metal' guitar, I am by no means a shredder. If anything, my style leans more towards Dave Gilmour or maybe somewhere between him and Adrian Smith. I use an SL3 because I like locking trems and thru-necks - no other reasons. It's just that those specs tend to crop up in Metal guitars :)