In terms of lens you should definately try for a 50mm Summicron - look for a black 50mm with focussing tab as it has the same optics as the version with built in lens hood that preceeded the current ASPH. If you can find one with mint optics but cosmetically a bit worn on the outside you should get something to suit your budget.
As far as camera body is concerned - go for the M6 Classic. There are quite a few in very nice condition appearing on the market right now with people upgrading to the M9/MP.
this is pretty much my dream set up. the 50mm cron w/ the focussing tab is what my friend has, and i instantly fell in love with that lens, the focusing, the build, and the way it renders photos. it just happens to be my favorite focal length too.
the buddy of mine uses that lens on his m6...and its like a dream to use. if i could find that same combination for about $2000, i'd get it. but it seems as though prices for leica HAVE gone up...
from what i'm seeing, price of a used m6 is good condition is about $1500, and price of the summicron 50mm f/2 tabbed, is also about $1500.
so that's a whopping $1000 dollar over my budget.
i might just wait a little longer, to see if prices come down. i'm in no rush, but i have been waiting over a year for an M system setup.
Here's the funny thing though, I've seen a used 50mm f/2 (latest version) sell for MORE than the price when NEW!! That has to mean a shortage...and probably not the best time to buy right now... not sure...
EDIT: would it be fair to say, that a fair price for a used summicron f/2 (tabbed) would be about $1200?