Ditto on Leon's link.
I also have an Olympus XA2, and it's fun, the previous owner clearly loved it (paint worn off at the thumbs), but it favors aperture over shutter speed, so motion blur isn't uncommon.
I also have a Ricoh 500G, which is like a poor man's Canonet, and it's a fantastic find if you find one, another $5 gem.
But, if I could have only one camera, it would be my Rollei 35 S. Not a true rangefinder, but just a jewel box of a camera. I did just buy an OpTech Digital D-Mini pouch, and it just barely fits, but it's perfect for tossing it in the bottom of a bag or pocket now.
Leon, I'm clearly going to have to pick up the Electro 35 Wide now, thank you very much. Like I needed another rangefinder.