I only just recieved my Black Hawk and Piledriver sets, haven't had time to have them installed yet, but next on my list is definitely a Mother's Milk set for the Fender 60's Roadworn Strat that I'm gonna buy as my next guitar, even though it's a bit far out in the future... To me, that pickup set just nails the John Frusciante Strat sound of Red Hot Chili Peppers' "Blood Sugar Sex Magic" album, which I love to death.
If I'm not buying the Strat as my next axe, I'm going with an Ibanez RGD2127FX and I'll probably be putting an Alnico Nailbomb in the bridge and a Cold Sweat in the neck. But that's just off the top of my head. Both purchases are pretty far off in the future, since I only just bought a Tele 3 months ago. Strat and/or a seven-string... I'm trying to remain versatile.