I got my new road bike, from a local California chain store, with 105 set. I've never owned anything this nice - just a 2003 hybrid. I knew immediately something was wrong - why would 105s sound like I'm dragging a box of legos behind the bike? Using my limited knowledge, I threw it up on the repair stand and it appeared the derailleurs were all out of whack.
I took it back, and the mechanic spent quite a bit of time on it. I was pretty happy, but he did tell me that certain noises were normal. I rode it around at low speed and it seemed okay.
Then, I finally got to ride it fast and it still sounded loud/awful.

So I went to the LBS I bought my hybrid from in 2003... The tech there was happy to work on the bike even though I didn't buy it there. It wasn't long before he had it running just like a song. Plenty of chain clearance all around. I took the bike around the parking lot and I couldn't believe how smooth, quiet, and fast shifting it was.

I bought a nice set of shoes and cleats/pedals there, even though they were slightly more expensive than I could get them from national retailers. Well worth it for the knowledge and time from the folks that work there.