I have a few LP's with BK's and P-90's.
The humbucker guitars have:
Tobacco Burst - Riff Raff & Stormy Monday - this is a chambered guitar and these pickups work really well in it. The slightly brighter sound works well (even though the guitar is still heavy!)
Sunburst - this is a 53 converted to 59 spec and has a Black Dog set. The guitar is really light and the Black Dogs work really well in it, they get all the classic Led Zep tones and more. It is still great for blues and clean sounds too.
Goldtop - PG Blues set. What can I say - PG Blues is such a great description of the sound. All the classic blues sounds that Peter Green got, but all the Gary Moore sounds are there too. A really excellent set of pickups that keep the clarity even when driving.
Going left to right, the Goldtop on the left is an original 54, with original P-90s. I no longer have the Custom, I will have to get another one day. The Special has one BK rewound pickup and one original, and has the greatest neck feel (it is a 60). the junior has a Pig-90 - lots more bottom end but still the P-90 growl. The goldtop on the right is a 72 reissue and sounds similar to the 59, but without quite as much mojo (though it is still a great guitar). The junior in the background is a 59 with the yellowest respray I ever saw!
Back to what pickups you pick, I would always recommend the PG Blues set if you want the older classic rock tones, or the Riff Raff/Stormy Monday for a bit more bridge drive.