In this same line of thinking, I've always wanted a Ferrari F40 ever since I was a kid. I don't need any of them fancy cars, I just want a solid driving experience. The F40 is light, doesn't have cupholders or a radio or even door handles! It's just built to be driven. Many writers and car reviews claim it as the best super car ever made, and it was the first street legal production car to break the 200mph barrier. But yeah, even if I could afford one, the insurance, repairs, and stuff for it might as well be a hole in the ground that I threw money into. http://en.wikipedia.org/wiki/Ferrari_F40 That or a Nissan GTR... such an amazing car and somewhat affordable.
They lose their value rather quickly: http://www.edmunds.com/bmw/m3/2009/ Also, episode 5 of the Neutral podcast has a lot of BMW goodness: http://neutral.fm/ The podcast is basically a bunch of programmers and tech geeks that decides to start a podcast on cars. Amateur enthusiasts. I dig it.
Worst on the market or best depending on your perspective. If you buy a relatively new 2 or 3 year old model you can get an incredible car at a comparatively great value. When I buy my next car, a three year old BMW will be on the short list of cars I check out I'm sure.
M3s are beautiful cars. I consider most BMWs over priced, but that was may even be under priced for the quality and power that comes from that thing. My co-worker drives an older used one that he put a lot of work into and that thing is STILL a beast. The new ones are just jaw dropping. A fine choice. I've always been an M5 fan because of the older style ones that were a little bigger and boxier. But all the M series ones are beautiful and fast cars.
My friend is an engineer at Borg Warner, who makes the turbo chargers, so I got ahold of their new brochure for the 2014 M3. They're switching back to a turbo I6 with a few less HP but over 100 more ft-lbs of torque. Makes me a bit drooly. I figure I can afford one around 2017 with some good luck.