I wanted to throw out a question to you regarding the speaker choice of the BW 602 S3 vs. the CM1 line. My equipment icludes a marantz 5001, B&W ASW610 subwoofer and the ccm series for rear speakers as well as a M1 for a cnter channel. Is the $360.00 upgrade worth it for the cm1 speakers?
Your weakest point by far in that setup is the M1 centre speaker. Don't bother changing anything else until that is sorted out first. You have a choice of speakers from B&W. B&Ws are all voiced similarly, although if you plan on going with a particular range (e.g CM), then you should get the appropriate centre for that range.
Sean, incidentally, another option you might consider which the wife may like would be an M&K LCR36. I use one of these as my centre and it works well, if not as well as I'd like. It'll be LOADS better than your M1 either way and it's arguably prettier...