How to evaluate speakers?


I have brought home two speakers to evaluate from the dealer. One is the Paradigm Monitor 11 and the other is the Monitor Audio Silver 6. I am using them for music using a Rotel 1060 amplifier. So far they both sound wonderful to me. I have to pick one of these two. But I can't tell which one I like better.
What are the things I should be listening for? I listen to a lot of jazz like Miles Davis, Coltrane, Oscar Peterson etc. A lot of world beat with lots of percussion, some classical.

How do you tell if one is better then the other?
keithjohnsondd85
Here's a good article that I keep bookmarked:

http://www.audioasylum.com/audio/speakers/messages/96830.html
Some great suggestions above. You might also check out Chesky's "The Ultimate Demonstration Disk." It contains a dozen or so well-recorded pieces, each selected to focus on a particular characteristic (presence, depth, transparency, etc.), and each preceded by an introduction advising what specifically to listen for and how the piece "should" sound on a good system. For me, this CD has been not only useful in comparing gear, but educational as well.
Buy some Green Mountain Europias, or Harmonic Precision Caravelles and use them as references! Hee Hee!
Thanks for all the replies.
One question. Will it make a difference if I connect one set of speakers to the speaker output A and the other to the speaker output B of my amplifier and use the speaker select switch to switch between speakers?

Thanks.
Using the A/B speaker selector switch should not make a difference. Just make sure that you listen to the speakers at the same volume level, because most people will choose the louder speaker as the better sounding speaker. So you may need to experiment a bit before you get into serious listening, for example volume level 3 for speaker A may be the equivalent of volume level 4 for speaker B.

Good luck, Rich