Well...at this point I've determined that the noise I'm hearing is actually the chain rubbing on the outside of the cage by the crankset. It does it when I'm in the big ring up front and/or when I'm in about the smallest half of the cogs in back. I've yet to find an easy fix. *sigh* Even the diagram on Shimano's site doesn't look like what I'm looking at, though I'm sure it's just angle.

It's frustrating...it's gotta be something that's worked loose over the last few weeks and therefore I'd think it isn't tough to correct. I was hoping not to have to go back to the shop yet again!