Speaker Question...first post on the gon

Hello. I'm wanting to put together a dedicated 2 channel system that is capable of simulating a "live" performance with blues, jazz and rock. With that being said, I value dynamics secondary to soundstage/imaging. I haven't had the opportunity to audition any speakers worth mentioning. Unfortunately, with work and other activities and a lack of dealers in my area, auditioning speakers is not even a viable option so I am hoping to make informed decisions in the used market, and with any luck find what I'm looking for the first go around. Currently the speakers in my hd (a/v?) uh, the room with my tv lol, have been pulling double duty with music. I have a Definitive setup with BP7001SC for L/R and BP3000 center and some smaller Definitive towers for rear. After much work with placement and a pair of Parasound HCA1500's bridged mono to the fronts with a small tube buffer between the amps and an H/K reciever I'm using as a pre/pro, I've managed to achieve pretty decent and dynamic soundstaging with 2 channel, for the types of music I listen to, or a decent improvement at least. I have a Parasound 5250 amp that can handle all 5 channels for movies, so for now I'm wanting to start with the 2 HCA1500's I have which are 630w at 8ohm bridged mono and use these for amplification. What speakers in the used market for $5000 or less, (preferably less :) will give me the bottom octaves at least on par with what I'm used to from my powered towers, tight/snappy midbass and a remaining audio spectrum that is musically dynamic but not fatiguing and with the ability to achieve focal imaging that essentially eliminates the sense of speakers as the source? I'm currently lookin on the gon at a pair of Vandersteen 5's (not 5a...not sure how different) and a pair of Vandersteen Quatros, mostly because I'm fairly confident that they will not disappoint in the lower octaves. Any opinions on these as well as any other speaker recommendations would be greatly appreciated. Thanks.
Another consideration would be Emerald Physics using your amps biamped rather than bridged. They will put out some serious sound pressure.
One of the few speakers I've ever heard that can do dynamics much like the real thing, were the UREI 813 studio monitors. They are big, really ugly and not exactly the most transparent speaker out there. However, they are fairly efficient, play LOUD, are relatively flat in frequency response and can swing dynamics like nothing I've ever heard before. With a good solid-state amp, they go low with the 15" Eminence woofers and the short foam horn tweeter is one of the better ones I've heard.

Again - not everyone's cup of tea - my pair are sitting under the stairs with the Altec 604 tweeter/midrange and Eminence bass drivers safely packed away. I prefer the transparency and vocal realism of my Magnepan 1.6/QRs.
What you want are high-efficiency horns. NOTHING else will deliver dynamics like horns. However, you may need to rethink the amp you have now.
2 Points:
1-The HK is your weak link. Your system can only sound as good as the weakest link.
2-Instead of bridging (great comments above), you can always bi-amp where they remain in stereo mode. Running 630 watts into the klipsch suggestion would be like sitting inside an airplane engine.
Final Note: That's a ton of wattage. Keep db in mind when looking. Very few rated 92db or higher in efficiency will be doubtful with handling 630wpc.
Chadnliz...what do you mean that Vandersteens don't play loudly? Mine get louder than I would want to listen to....and too...in what part of the hall do you usually get tickets? Dynamics in the 1st row are way different than the middle of the hall, or in the back. I like to sit in the middle of the hall, and for that, my Vandersteens are fine. I do suppose, you need a proper amplifier...ie, a good one with adequate muscle.