I realise this is very old thread. However, topically I have just spent quite a bit on my 2009 26" Trek 8500 9-speed triple hardtail.
The BB was starting to show signs of play and the chain was starting to skip a bit.
I was thinking of getting rid and getting something a bit more modern as parts were getting hard to source. I did consider maybe even a double bouncer this time (Trek Remedy 8 had crossed my mind).
However, I love the bike and it does all I need and it would be shame just to give up on it.
So I threw best part of £200 in bits at it. Hollowtech II BB, middle and outer chainwheels, cassette and chain and Ti brake pads front an rear.
During the strip I found that the BB drive side was fine, but the non-drive side showed sign of water ingress. I think the old one was a Holowtech BB51 which had issues with seals. The seals were just washers covered on rubber. The BB51 was replaced by the BB52, which has proper seals.
It rides like a new bike again now.