These work well enough in all conditions (winter, summer, hills, whatever). Just put some decent pads. Shimano Acera:
http://www.chainreactioncycles.com/M...?ModelID=34700
These are a bit better. Shimano Deore.
http://www.chainreactioncycles.com/M...?ModelID=39004
Deore are some 50% more expensive, but that's like 10 euros extra for better and more durable brakes. I bought Acera and have been happy for over 2 years and over 8000 kilometres.