Get the Tektro 800a brakes -- only about $20-$25 and they're still being made for frames that require nutted brakes. They're not as pretty as new recessed-nut calipers, but so far they're working out well for me. The only issue I had with them was that I couldn't stand the old-school brake pads they came with, and swapped out for a new pair of Shimano pads so I could adjust them with a hex key.