The best is for the OP to really go out there and test/listen to each speaker to at least get a glimpse of the sound he will be hearing and establish his preference.
At a certain price point, I could say there is no best speaker cause one brand may be good for one and not good for another person. So it is really hard to recommend without the OP hearing it. And, to top it all, there could be no one that has heard all the speakers in the list.
For me, a speaker first has to be transparent or detailed, in a sense that it is able to output the character of the connected components from source to amplifier. I think this what makes a speaker good. If you connect a laid back system, what comes out should be laid back. If you connect an ear piercing system, what comes out should be ear piercing.
For frequency response, it will depend on the design of the speaker. Don't expect extended bass for most bookshelf speakers. Also, you need to match the size of the speaker to your room size. A powerful floorstander will not sound good in a very small room.
My first step in picking a speaker is to look at the maximum budget I can afford. In the case of a 20k speaker, I would not expect extended bass output but rather concentrate on the mids and highs performance of the speaker. Bass can later be augmented by a subwoofer or the need for more bass will depend on the type of music that will be frequently played. Also in this price range, if the speaker has loud bass, in my experience, the mids and highs are compromised.
I guess, the OP should really set aside some time to test the speakers. He should consider it a journey in finding the speaker that suites his taste. For imported brands, there are reviews he can check on the web as a starter. Another would be to listen to PDVD member's set-up and hear how they sound. From there he can establish his preference. Also be aware, that your first purchase (even if you found what you like) will never be the last ....... good luck on your hunt and enjoy!
