I just wanted to put a good word for this divot repair tool I bought at Stonebridge pro shop. Small, lightweight, good on hard greens, and it only cost $1!!!! I think they're called Golfmax Divvy Golf Divot Tool. After trying everything from expensive repair tools to using a regular tee, I think this is the best thing for fixing divots. Stocking up on these this winter.
http://www.golfmaxusa.com/mmGOLF/Images/248-Actual.jpg