I have a 2005 Trek 5000. I have put 10000 Kms on it in the 4 summers I have been able to ride and this winter I put a new Dura-ace 7800 crank and bottom bracket on it. I had to replace the chain and rear cassette as well. It had a Shimano 105 crankset on it. Each year I upgrade something to keep me interested. I went for my first couple of rides this past week and what a difference. It felt like a different bike. I should have done this earlier. What upgrades did you feel made the biggest diffence in your ride?