Maybe I'll open the door to a lot of ridicule here, but I'll post anyhow

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I've had a lot of different speakers over the years- Fishers, Paradigms, Infinitys, Polk Audios, JBL's, Cerwin Vegas, Bose, Sonys, MTX, etc.
When I buy speakers it boils down to 2 things- where I'm at financialy and how good they sound to me. The numbers, charts, and everything else doesn't mean that much to me. I'd rather go into a room blind folded and listen to a bunch of speakers w/ 3 good test songs. I think the 3 best songs to test speakers would be Dire Straights, your latest trick; Pink Floyd, welcome to the machine; and Metallica, dyers eve (a good one for durability).
To me the best 3 were the Paradigms, the infinitys, and the polks. The infinitys sounded good until you pushed them, the woofers couldn't take much abuse. The pardigms sounded decent even when you pushed them, but they just seemed to me to be slightly lacking on the highs.
Out of all of them, I really liked my Polk R50's. They seemed to me to have great highs and played well at loud volumes as well. I also like the JBLs I have now; those have great highs too.
I know I have a lot to learn but just wanted to throw my 2 cents out there. I always judge my speakers w/ music and not movies. I did figure out that the receiver plays a larger part than I ever new as well. I figured this out when I got rid of my 5 year old Denon and picked up my new Yamaha- WOW! What a difference just a receiver makes! The Yamaha sounds AMAZINGLY better w/ movies but the Denon sounded a bit better w/ music.
Maybe TMI for the question 'what's the best speaker you've ever owned', but just wanted to help you audiophiles know how I come to my conclusions

! Long story short, the Polk R50's to me were the best sounding I've owned. Had to get rid of them when I bought my house 6 years ago though cuz towers don't work in this living room.