What a great site for inspiration. I thought I'd pass along some pictures of my new commuter.
I started off with an old '78 Sekine 10 speed I picked up for cheap after posting an ad on Craigslist (I attached a "before" pic). I stripped the frame, gave it a quick rattle can paint job and started replacing parts. This was a budget project so the parts list isn't anything too spectacular. Mavic CXPs front and rear with generic Formula hubs (fixed/free) and a drivetrain kit from IRO Cycles. Although it's set up to be a flip/flop, I just haven't gotten around to picking up a singlespeed freewheel for it yet. Running 46x17 fixed is all I need.
I documented the project if anyone want's to take a look at the progress from start to finish: http://flickr.com/photos/brettohland/collections/72157605105590358/