The Jupiter-9 85mm f/2 is a very cheap and nice lens, especially if you intend to use it wide open. It's a preset lens, so you need to stop down manually before you take the picture, but it has a very nice signature for a low price.

Also of interest, but shorter, is the Helios-44M 58mm f/2, a russian copy of the Zeiss Biotar. The "M" one has auto diaphragm. I've just started using it and will have pictures later on, but the construction is very good for the price.

Most of the Carl Zeiss Jena are worth checking too. I had a 50mm f/2.8 Tessar that really had a nice look, and I keep chastising myself for selling it. The 135mm Sonnar would probably be very cheap (nobody seems to like 135mm).

Otherwise, the Takumars are in many respects the cream of the crop in terms of bokeh, build quality, colour transmission, etc. My 135mm f/3.5 Takumar was incredible and cheap. The 105mm could be a good, albeit harder to find option, but the 85mm are impossible to get for a reasonable price.