Ok I've been playing for about 10 months now and I'm considering upgrading my squier (affnity).
I play a bit of everything... First of all I want to put in a humbucker on the bridge and then later on 2 new single coils for the middle and neck positions.
Any suggestions on which ones to get? I heard good stuff about the seymour duncan hotrails but I'm not to sure about the whole single coil sized humbuck thing... And I have absolutely no clue on what kind of single coils I should get.

ehh think of pickups as an asset... u can always take them out and pout them in ur next guitar..
go to the seymour duncan site and theres sound clips on their pickups.. c wat u like
p.s. i neva knew the affinity series has HSS setup
my humble gears:

Ibanez Prestige RG1570 with EVOS!!!
Epiphone Std LesPaul with PAFs

EVJ -> 1960av
EHX Metal Muff, Big Muff, Small Clone
Ibanez WD7, VOX V847, OD-3, BLT slap echo

FIRST Member #11 of the EHX Users Guild
Most strat copies have space for a humbucker. You just have to change the pickguard and get the pickup. Ya, check out SD.