well what style of music do you play , what covers ?
for more of a classic rock with a brighter sound but a little more bass , the fred or mo'joe would probably work
for more modern rock that needs an edgy sound , the dimarzio d-sonic with the bar to the neck , for a little less but more definition the d-sonic with the bar toward the bridge .
you may also consider the
super distortion , althought it's cleans are a little lacking you could make up for that since you have the middle single coil . Alot of guys use the super d in thier EVH strats , it can do a fairly good van hallen tone , or great rock metal tone .
as far as neck pickups go , if you want something with alot of balls but is really clear , or if you like going shred style , the humbucker from hell is the best imo . It also cleans up beautifully , truely one of the most versital neck pickups i have played or owned .
if your looking for somthing a little fatter with a bit warmer sounded but with good definition the air norton is great .
if you have a really mid heavy amp with a lot gain , or just want to smooth your sound out the steve's special isn't a bad choice , i personally didn't care for it too much because although it is a fairly high
output pickup it doesn't act or sound like one.
as far as single coils go , i have only ever used the chopper and fast track one , both sounded sorta simular but they both had sort of an andy timmons style tone under distortion .
