It depends, but as Monny said, Cruisers are good if you like the more modern heavy sounds.

If you looking for a classic strat sound with twang then get Area 51's or Blue Velvet for a more bluesy sound.

If you want classic tones with humbucking function i recommend HS-2/3

I used to own Cruisers, then changed them to HS-3's.

Duncan Quarter Pounders are cool if you after that Deep Purple Blackmore Tone.

I think you should look for a pup that gives you a classic tone cause thats the beauty of a strat =D

or you could get a fender replacement pickguard for a S - S - S setup,

that way you definately have the classic fender tone, the S.D and Fender pups give the best traditional fender tones, DiMarzio is nto bad but not much choices, check out the Area pups. . . bloody twangy and clean with no hum. . .

For fender just dotn get the lace sensors. . . they're not that good. . . had a friend who used to have em. . sold em off cause it just doesnt sound all that great. . .

most single coils can't coil tap tho. . unless you look for those humbucking single coils. . so yea. .