I read an article recently that suggested bringing CDs that you don't know very well with you when you audition a speaker. This way you're not bringing with you the preconceived notion about how your music "should" sound.
The basic idea the author was trying to put forth was that the most accurate (and thus "best") speakers are the ones which bring out the most differences between CDs.
It makes more sense when you look at it the opposite way: the "worst" speakers are the ones which tend to make all your CDs sound the same.
The article was a fascinating read. If anyone is interested, I'll try to find it.
