I *just* (yesterday, 31July) bought my very first MF camera - a Minolta Autocord TLR for the specific purpose of Street photography. I can't give 1st hand recommendations, only offer what i've been reading (non-stop) the last couple weeks. The 75mm Rokkor lens is regarded as sharper than all the various Yashica Mats and rivaling the Rolleicord (or Rolleiflex - can't keep the Rollei models straight) of the 'Tessar' lens formula. I'll get flamed for mixing the Rollei models up, but you'll get the point.
The main consideration with the Minolta Autocord, aside from ensuring it has clear optics, is making certain the focus lever moves smoothly. Evidently the lever will seize in position due to the ancient lubricants. This can obviously be cleared up with a CLA (or even delicate use of lighter fluid), but it's nice to get one that's good to go.
The one i bought needs a new leatherette, but Morgan at cameraleather has the just-right-solution called GripTac. For about $26, my Autocord will have some serious, hardcore street machine armor!!!
I've been borrowing a mint condition Yashica Mat 124 from a friend and it's pretty sweet (coming from 35mm) - that ground-glass viewfinder is amazing! However, i'm a bit of a Minolta/Rokkor buff so as i read the generally raving reviews about the Autocord's Rokkor lens, it became my obvious destination camera (there was also something about having a 'flatter' film plane? than the other TLR cameras). They're definitely easier on the wallet than the Rollei/Hasselblad/Bronica/Mamiya offerings - all around a nice balance.