I couldn't resist chiming in. The M3 and MP are getting way too much attention!
Yes, the M6 is still a fine camera even after the battery goes dead.
Mine is an M6 "Classic" (non-TTL) that was made in 1996, according to the serial number. I bought it just recently, complete with the original red-velvet lined plastic box, documentation, and outer packaging for what I consider to be a very reasonable price. It is in perfect shape ... still has the plastic on the bottom plate. Of course it won't stay that way. I'm already using it a lot, alongside my M8.