I’ve owned two rangefinders my Voigtlander Bessa R3m and a Yashica Electro. I’m updating this post day by day so please ignore it for a while. 
Leica makes some of the most expensive camera equipment in the world. I am going to leave it at that.
Leica Links
The mothership, Leica Germany.
Leica on ebay. Take advantage of the recession and buy used.
Nikon Rangefinders
I don’t know much about Nikon rangefinders except that they sell at near Leica prices and that Cosina-Voigtlander still makes some lenses for them. I would love to own one but they start at $1,000 used and that is beyond my price point.
Canon Rangefinders
Olympus Rangefinders
Olympus made a line of high quality rangefinder cameras that like the Yashica are known for being a poor man’s Leica. The Olympus rangefinders were a little higher quality than those marketed by Yashica and usually cost a little more on ebay.
Yashica Rangefinders
My first rangefinder was a Yashica Electro which is a fabulous metal camera made in the 50s and 60s as an entry level rangedinder. Millions of them were sold and you can still find them on ebay. They are often called the poor man’s Leica but are actually better beause they won’t cost as much as a used car.
Yashica Links
Zeis Rangefinders
Do you want to buy a really expensive Voightlander Bessa? Buy a new Zeis-Ikon which is made by Cosina-Voigtlander for Zeis.
Contax Rangefinders
Russian Rangefinders
During the hayday of rangefinder cameras, the Solviet Union spent a lot of time and energy making reasonably good Leica knokoffs. They even adopted the M mount and sell some pretty decent although antiquated glass for M mount cameras.