I have an old Epiphone Les Paul, and I want to do one of two things: Either rewire it for Jazz/Blues, or get a new guitar for Jazz/Blues. I don't need suggestions guitar-wise (I love the idea of a Gibson SG Classic or an Ibanez semi-hollow).

What I do need is suggestions for which route to take, and if it's the pickups route, I need to know what to get. Honestly, I love the look of my epi, and I love the feel of the neck. So i was thinking of a Seymour Duncan Jazz in the neck and a PAF Pro in the bridge. Basically I want something mellow in the neck and something a little crunchier in the bridge, maybe capable of some higher gain sounds.
I'd say go with new pickups if you plan on sticking with the jazzy/bluesy sound - a lot cheaper than buying a new guitar.

However if you like the tone of your guitar now and plan on using its current tone in the future then you should get yourself a new guitar. That way you will be able to get your jazzy/bluesy tone and you won't lose the current tone you have!