#1
First off, I'm pickup-retarded. I have no idea what to look for.

http://guitars.musiciansfriend.com/product/Fender-Deluxe-Fat-Strat-HSS-Electric-Guitar-Black?sku=510477

Are the pickups worth replacing? Or are they good enough as is?

This is the exact guitar (the black one). The pickups are ok, I guess. Maybe my expectations are too high, or there's some faulty wiring (they're pretty hummy).

I'm going for pickups that can go all over the SRV spectrum, get the David Gilmour sound (Shine On You Crazy Diamond clean tones/In the Flesh distortion/Comfortably Numb lead tones, specifically), and the Sweet Home Alabama tone. I'm also looking for a bridge p-up that can handle some gain, but I don't want to use a humbucker if that's possible (don't they make stacked 'buckers in a single coil body?), for aesthetic reasons (I've never liked the way a Strat looked with a bridge 'bucker).
Remember who you are, and Who's you are
#2
Ummm.... the guitar you have the link too already has a humbucker at the bridge... you can't really get rid of it unless you get a different pick guard.... otherwise there would be a hole... Anyways personally I'm gonna recommend EMG's, but you could try some others too. EMG's are known mostly for metal, but they're actually incredibly flexible, good for everything. It depends on your budget though, 3 EMG pickups is gonna run you about $300. Shop around though, read reviews, and find something that sounds good to you.
#3
I plan to get another pickguard. And I'm not going to go the active route, so EMGs are not an option. :/
Remember who you are, and Who's you are