Lots of recommendations.

Cheap: Tektro and off-brand stuff on ebay
Reasonably affordable: Avid Shorty 4 or Shorty 6
Less affordable: Paul (Stoplights, Touring, a few other models)

There are lots of niche products made for various forms of racing, especially cross. Some beautifully designed stuff out there, but mostly pricey.

I'm looking for really nice levers for cantilever but not finding much. Paul Love levers are nice, but expensive. Hopefully this thread will turn up some more info...