It depends upon what sort of style of music you play. If you're playing some smooth, smoky laid back sort of thing which you need nice clean tones for, then the stock pickups are fine. If you're looking at anything where you're going to crank the gain up a bit, ie blues, rock, metal, punk etc, you are best off changing them for some aftermarket pickups.
Choices of pickups? There's a heck of a lot of choice out there, from cheap-ish ones, like Kent Armstrong's to expensive, like Fralins etc. Most people go for Seymour Duncan's 59 neck & either JB or Custom bridge.
I've got 2 Love Rocks at the moment, and both of them are fitted with
www.bareknucklepickups.com pickups. I've had SD's in one of them (a 59 and a JB), but I got really fed up with their clinical sound, as well as the lack of tonal spectrum and clarity (IMO), so I started looking for another pickup which would suit my needs. As I'm in the UK, all the US boutique brands were just way, way too expensive, and there didn't seem like much choice, then I stumbled upon Bare Knuckle's. I was lucky enough to find a shop that had a guitar with the pickups I wanted in store, so I tried it out, and ordered them there and then. I've since gone on to buy 2 further sets for other guitars, I like the pickups that much.
They're scatterwound, by hand, in the UK. Their customer support is second to none. Their pickups sound absolutely amazing, with loads of character and clarity and "zing", I can't recommend them enough! :wink: