speaker upgrade

after cobbling up a sytem 2 years ago that would just get me going, i am looking to upgrade speakers. i assembled the parts express
BR-1 kit which is driven by an audio refinement complete integrated amplifier. no fancy cabling and i am currently using a sony dvd player as a source. i would like a speaker that mates well with my current amplifier and would allow me to justify the additional expenses of upgrading ancillary components and source. i am looking for a bookshelf design and am willing to spend $500 +/- $100. prefer used and diy (need pre-assembled cabinets though) is fine too (value is king).

room is about 15' X 17', speakers arranged on long wall, hardwood floors (concrete underneath) with area rug in front and typical living room furniture. placement of speakers into the room is not a problem (currently they are 36" from rear wall).

i listen to all types of music except country. jazz, funk, pop, hip-hop, electronica, rock, and some classical make up the majority of my listening preferences.

some speakers that have caught my attention:
quad 12L (used)
von schweikert VR1 (used)
ed frias AR.com diy kit

would like something a bit more refined than the BR-1s. the amount of bass from BR-1s is sufficient, but would like it a little tighter, taut. clean mid-range and non-fatiguing highs also important.

thanks for reading. any comments/help is greatly appreciated.

best regards,
I'd say Green Mountain Audio Europas would probably fit the bill. I just replaced some Spica Angelus and the green mountains are the best monitor speaker I've ever heard (not that I spend much time in dealers, though).

Plus they're designed and built in the US and the company give excellent after sales service. I've called a couple of times and Roy, the designer has spent 10-15 minutes on the phone discussing room setup, cabling, music types ... I've never experienced this with another company.
I would take a serious look at Selah Audio's SA-1 monitor.
It is available as a kit or complete speaker. Completed is $850 I believe, kit is $475 with x/o assembled. The SA-1 has a Fountek ribbon and a Vifa 7"xt woofer. Assembled may be over you budget, but this speaker is worth consideration.

Very detailed with nice bass and the last monitor you will probably own. I audiotioned the SA-1 and it convinced me Selah knows speakers. I just picked up the Carnelian from SelahAudio.com

Worth at least checking out. Also, you can sign up for an in home audition, doesn't get any better than that. Listening in your environment with your gear.

PS the Europas are very good for the $$ but the SA-1 takes it to the next level in monitors.
Good Luck