I'll second everything said above about the CR720's. They're great and they're easy to set up if you don't need to do much geometry tweaking -- say for narrower posts or for a change in wheel size (e.g. 27" to 700c).

For an older bike, I've normally picked up some older Dia Compe brakes like 960's or 980's. They work well, they're plenty adjustable to work with narrower posts, they look right at home on older bikes, and they can often be found on eBay in great shape.