Upgrade Paradigm Studio 20s for music & movies

I am, for the first time in my life, not *bothered* by my home stereo system. My system sounds good, and I can sit down and listen without glaring flaws ruining the experience.

However, I expect that I'll want to upgrade sometime. A friend of mine is willing to buy my current speakers (Paradigm Studio 20 V2s and Monitor CC350) for $650 (is that a fair price for both of us?), so it's got me wondering.

My Current System:

Denon 3600 Reciever (120W x 5)
Paradigm Studio 20s
Paradigm Monitor CC350
Advent Rears
Cambridge Soundworks PSW1 Sealed Subwoofer (12" x 140W)
Low to mid-range Audioquest cables

HOWEVER, the Denon and Advents are not mine (my room-mate requires surround sound in the living room). Sooner or later I'll be using my Rotel pre and Bryston 2B-LP amplifier.

I listen to a wide range of music (from hard rock and electronic to classic rock and easy listening). I'm primarily interested in accuracity, resolution, and impact. I want to hear the recording in all of it's flaw and glory, nothing more, nothing less.

So, what will it cost to make substantial gains over the Studio 20s (for stereo and to a much lesser degree HT)? I plan to continue using the PSW1 subwoofer for some time (I've never been unhappy with it). What would you recomend listening to?

I'd like to buy a pair of speakers for less than $1500 now. If they aren't good enough, I'd want to move them to the rears and spend upwards of $4-$5k when I have more money in the future. What can I get in those price ranges? Is the price range too low for my purposes?

I know that this is a lot to swallow, but I appreciate any advice.

Thanks,

Nick