Jon,
I was in a position just like you're in now. I was saving for a 5dMkII when all of sudden I decided, and wanted, to try a completely different shooting experience. I have SLR (nikon and minolta) and DSLR (canon) so I thought I would try a film rangefinder camera and see if I like it.
Long story short, I bought a Leica M6. Prior to that I had never shot a rangefinder and the time I received my M6 was the very first time I put my hands on a rangefinder camera. It was like a gamble since the camera was not cheap, but the way I see it, if I didn't like shooting with an RF, then I can always sell it later. But as it turns out, I love shooting with my M6. I seldom carry my dslr now.
So I would suggest you just go ahead and buy a rangefinder, be it M2, M3 or M6. If you don't like it, you can always sell it later. 🙂
Bob