>>I would have to say the M80s make a fine kick ass Rock speaker

Absolutely... Like you, I prefer the M2 / 22 / 60 / 80 sound.
I found a comment from Alan in a post earlier this year which might help the M50 vs. M60 question...

>>The M60s have ever so slightly less output in the midrange and highs than the M80s, but overall they are extremely similar in tonal balance. Not so the M50s, which are quite a bit softer sounding and less detailed in the mids and highs. The M40s are even more laid-back than the M50s in this respect.

http://www.axiomaudio.com/boards/showflat.php?Cat=&Board=HT&Number=43673&page=&view=&sb=&o=&vc=1

... and one of my first threads where a bunch of nice people jumped in with advice and comments about the different speakers and their sounds :

http://www.axiomaudio.com/boards/showflat.php?Cat=&Board=ST&Number=60501&page=&view=&sb=&o=&vc=1


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8