Here's the bike I've been riding to work lately: '88 Trek 660, converted to 42-16 fixed gear.
I bought the frame second-hand for a song, had to buy a new rear wheel (Sun rims, Suzue flipflop, Surly cog, D/A lockring), Sora front brake, and new brake hoods. Everything else is from the spare parts box, including the mismatched bar tape, RSX crankset, and RSX/Mavic CPX21 front wheel. The 19in frame is a little short for me, but with a 120mm stem and a fair bit of seatpost, it fits remarkably well.
I love this bike.