One of the best systems for that kind of money would be the Martin Logan SL3 mains, Aerius or Scenario or Script surrounds (depends on room size) and ML Cinema center. A sub that gets it with these is the Sunfire MKII. The total comes to close to your budget i.e. new or even less on slightly used ones/demos. It is a fab setup for music and HT. If you can go the extra for the Requests speakers it would be even that much better on the music end. Transparency and clarity are great.
Speaker Suggestions
I am currently using the B&K AVR202, with a Marantz 930 DVD, Kimber 8TC cables and Wireworld Interconnects. I am using a Definitve Technology setup all the way around and looking to upgrade. I have about $6,500 to spend on all speakers including a sub. My room is 25x17 with 25 foot ceilings. Any advice?