I've been commuting on an old Miyata 210 a friend gave me. It fits me well and I've added a few touches that make it extremely comfy to ride.
The big concern I have are the wheels. The original 27" wheels had badly rusted spokes, were on the heavy side (this said from a guy weighing 210lbs). For amusement I put on a set of 700c Mavic classic pros that I also scored for free from a yard sale. I had to adjust the canti brakes, but the 700c wheels fit. With 700x35mm schwalbes this is a nice handling ride. I even got an 8spd cassette to shift. It took a little messing around with limit screws, but I've got almost 800 miles with this setup.
Issues:
- The brake track on these rims is really beat up and these won't last a whole lot longer.
- The wheels were out of true, out of tension when I got them. I've built a few sets of wheels and used my experience to straighten them out. Unfortunately the back wheel is again working itself out of tension (and true).
- I've no idea how to service the Mavic hubs. I'm normally a cup and cone shimano hub guy - but these were free.
- black rim/spoke/hubs on this bike looks stupid

see:
http://www.flickr.com/photos/14139005@N02/sets/72157624954970683/
Initially I wanted to spend the absolute minimum on this bike. To date I've got around $50 into it, save for the Brooks B-17 I had already. I'm interested in building a wheelset, but not sure what components would be appropriate.
- Do I stick with 700c for modern tire selection?
- Do I go with a freehub/cassette to take advantage of modern parts?
- What about rear dropout spacing? I'm stretching to fit a 130mm axle now, but a 126mm hub wouldn't work in other modern bikes.
In any case, I don't need some "bomb proof", ultimate tourer. I need to be able to ride this around 18mph to get to work on time. Perhaps I should just build some sensible road rims out of modern components (ultegra hubs on velocity rims perhaps).
Thanks for any ideas or comments.
-Sean