You might want to check out this listing of speaker tests. Probably only a few of the speakers mentioned in this thread have been tested, but at least this will give you an idea of their overall frequency response. This is an objective approach as well.
http://www.soundstageav.com/speakermeasurements.html
Overall, I don't think there is really that much of a 'night and day' difference between speakers. I have played with equalization and speaker placement, and have made two very different speakers sound almost identical - without adjustments they sound very different.
I think if you find something that has a fairly flat frequency response, you can adjust it to your taste and be happy with it.
I just read a pretty interesting article on speakers/measurements/preferences on the audiocritic.com site. Look for the archives and issue no. 28, which was written by an industry professional.