I'm surprised that noone's mentioned the way that I got into MF film, and that's the good old Pentacon Six. For a start, they're cheap, and they're reliable, and they've got lovely lovely Zeiss lenses to go along with them. They've also got www.pentaconsix.com, for all the info you could ever want about anything ever made for them (same way that www.the-digital-picture.com got me to choose digital Canon over Nikon, information is king).
For a body by itself, maybe $60-100. Prism $50, or Kiev 60 Prism $10-40 plus prism adapter $20-30. Fresnel Screen $20. Biometar 80mm f/2.8 $80-100. Get all of that in a guaranteed working CLA'd kit for $200 (if you need names of trustworthy people on ebay to buy from just ask me, 'cupog' and 'grizzly33bear' are good places to start).
Some people shy away from the Kievs, but i've never had a problem with my Kiev 60 either. In fact, it looks so much more well built than my Pentacon 6 and the shutter just sounds a lot more definite (maybe my P6 has had a hard life, K60 was well taken care of and CLAd before I got it). Never had a problem with my Kiev 88CM Hasselbladski either. TTL Spot Prism for $50, *and* it fits all Hasselblad models too? Yes please.
The lens selection is great, Zeiss made 50/4, 80/2.8, 120/2.8, 180/2.8, 300/4. The Soviet ripoffs can be good, can be bad, the only thing that anyone agrees on is that their Quality Control wasn't the best (if it existed at all). Things like a Zodiak 30mm f/3.5 Fisheye, a direct ripoff of the Hasselblad version for 10% of the price (and maybe 95% of the performance).
Quality of others is reflected in the prices, an uncoated Volna 80/2.8 can be had for $20, hit or miss, and resell it if it's soft for the price of shipping and a test roll or have a nice paperweight or "soft focus" lens. (ok, i've never had one that bad, but i cleaned my Zeiss Biometar 80/2.8 and misaligned the elements, now it's Soft Focus only).
And the best part is, there's adapters to anything and everything. That's how I got into them, Tilt-adapter to my EOS, since bought a Shift adapter too (if only they did both), $100 or so each on fleabay. Can mount Kiev 88 / Hassy 1000 lenses on them with a tiny adapter ring for $20. Even better is an adapter to Mamiya or Contax or Pentax 645, I bought my Mamiya 645 a year before I got my first mamiya lens because I just used it with my P6 glass.