I have no idea what the Enya CD is mixed like quality wise, it's probably very good, but thought I would mention that along with your favs, bring along some CDs that you know to be very well produced. M60s or M80s are so accurate that they will really make obvious the flaws in a poorly recorded CD. This can trick you into thinking they are at fault instead of just being the perfectionists that they are. Alternatively quality recordings will bring out the true amazement factor that these speakers are capable of.
Search this board for suggestions that are too your liking but here are some old standards that I use for demoing my speakers as they are also fairly recognizable by most people.
These are listed so often, my non-conformist side hesitates to write them but all the same, you can't go wrong with them.
-- Pink Floyd, "Dark Side of the Moon" (remastered, but original is exceptional as well.)
-- Dire Straights, "Brothers in Arms" (remastered, but original is exceptional as well.)
-- Holst's "The Planets" by Mehta and the LA Philharmonic (many parts of these pieces will be recognizable even to the non-classical fan for their use in many movies.)
Dianna Krall's DVD, "Live in Paris" is great as the female voice is a great tool for evaluating speakers, (although some might say her voice is too deep for this exercise) but lots of clear jazz instruments to evaluate here too.
Dave Matthews and Tim Reynolds' DVD, "Live at Radio City", is a must to hear guitar strings like they are truly in your living room.
That's just a few that will blow you away in a demo but bring stuff you are accustomed to listening too as well.
