I've got the dreaded elusive creak going on in my crankset. It happens only when climbing and standing on the pedals. It's getting to be pretty bad and I'm surprised something hasn't broken yet. Here's is what I've checked:
Pedals: removed and regreased the threads and the pedals themselves
Cleats: rode with my sandals, the creak didn't go away
Crank bolts: tightened
Bottom bracket: the mechanic at the Performance store took off my crank and tightened the bottom bracket, saying it was a bit loose. This did not help. He also said it didn't need more grease.
I also switched out the seatpost and that wasn't it either.