Bike sounds (bad ones)

This is my database of creaking and other unpleasant sounds:

1. Seat collar creaks! It seems that the sound comes out of handlebar, pivot, crank, chain, pedals, BB. You freak out and think you bike is falling apart. It may be that it is your seat-post collar that is the culprit for this nerve-wrecking experience of yours! Symptoms:
1. Stand up and pedal- no creaking
2. Stop and push on handlebar- no creaking
3. Compress suspension while moving and not pedaling-no creaking
4. Tighten seat bolts- still creaking
5. Take of seat-post collar, lightly grease it and try now. No more creaking? Then the culprit is the seat collar!
2. You hear a loud single click when starting pedaling up a steep section or putting a lot of torque on your crank trying to go over an uphill obstacle
1. It is possible that your freehub (if it is an XT hub) is loose or your freehub broke down (Hope). In either case, the freehub may jam and you will have to walk.