Affordable Newer Speakers

If you have a already have a sub, you really can't lose with the Pioneer Model: SP-FS52... These run $249 retail and I've seen them for less. Once they break in they are surprising. I don't think you'll find anything for $500 to beat them.

A $500 budget with the hopes of surpassing what once was a 1k speaker in its day is asking a lot...that said...my experience with Minis is that they image well, but bass can be wooly and overly warm...I would opt for speaker with tighter, somewhat leaner bass...Dynaudio comes to mind...or try a Hsu sub

KEF LS50s are awesome, new-generation speakers.

@Tgrisham has a good idea there...Music Direct has a clearance
section with some great deals on stand mounted speakers. Epos,
Wharfdale, Focal, etc. I think the best one is the Focal Chorus 806 V for
$600 new, down from a grand. A little above your limit, but likely
worth it in the long run.

"The Chorus 800 Vs all handle the transitions from bass to midrange
to treble with rare finesse. And when that happens, the speakers'
technology melts away, and all you think about is the music."
– Steve Guttenberg, Home Theater

Anyways, some options to research.
mot

http://www.musicdirect.com/p-41246-focal-chorus-706v-bookshelf-speakers-pr.aspx

449 shipped....great deal