I went through a similar process two or three years ago and I ended up with a system that sounds great with music and is also excellent with DVD surround. Most important to me is something that sounds good with music but, because of that, I enjoy movies more when I can appreciate the subtleties of the music. A decent surround system will do both.
First of all, I suggest you commit to upgrading your receiver since so much has developed in recent years in that technology. Try to get something that runs on the cool side since it'll be on many more hours as it will increasingly be used for music, movies and TV - especially if you go HD and have 5.1 TV broadcasts, which we'll all have before too long. In your price range, I think Yamaha, Onkyo and Denon are the best choices. I'd stay away from Pioneer, JVC and Kenwood. You can find good features there at great prices, but they've tended to run quite hot when used a lot.
As to speakers ... If your floors are still producing excellent sound that you like, I suggest you keep them as your fronts and build around them with other Bostons since compatability is important. It's all a matter of personal taste, but with music listening as your premium, I wouldn't comprimise on the fronts - they are your prime speakers for music. In my testing, I wasn't satisfied with bookshelfs as fronts when I listened to music. Next, for my money, the most important speaker for surround (movie watching) purposes is you center channel. Many people make the mistake of not prioritizing this, but most of the sound in movies (all dialogue and much else) comes through the center channel. The other speakers are really for special affects and ambience. Next, get a good subwoofer. This is a speaker you can consider a different brand if you want. I've had Infinity and Velodyne, and if you can get a good price on Velodyne you can't go wrong. I actually saw Costco carrying an 8" version - you might check it out in your area.
Last, the rear surrounds. I think good quality book shelves work here. Get some inexpensive colored chain and you can hang and suspend them from the ceiling or wall to angle them perfectly to your listening area. In the context of a movie, relatively little sound comes from them but what does is what produces the surround affects. If you keep your fronts, get Bostons for your center and rears.
If your rears are good enough and compatable with your fronts, you may find yourself listening to CD music in a four channel or disco type mode - it really fills up the room with good rears. However, with CD music you'll never listen through the center channel.
Music DVD's are another matter. Since I've had my new system, I've become fond of viewing and listening to high quality digital surround music DVD's that are made for that purpose.
Some mail order vendors will allow you to try out the speakers and return at no cost if they aren't to your satisfaction.
Another idea is to work your local Audio stores to find out when BA models are changing. When I did mine, Infinity was going through a model change and I was able to get some great prices.
Another possible trick to save some money is to find a vendor where you can purchase a receiver that was part of a rack system and goes by a different model number but is the exact of one the manufacturer sells as stand alone. I don't know where you are, but stores in the NW like Video Only have been known to do this.
Definitely consider on-line savings. Try a website like techbargains.com and wait for a screaming deal on a good receiver.
Good luck!
I'm planning to re-work my family room. My plan is to consolidate current stereo system with TV/DVD. One goal is to reduce the speaker size to free up floorspace; perhaps bookshelf speakers mounted on the wall. Music is a high priority, followed by good audio on concert/music DVDs. Lower interest in watching a movie in surround-sound, etc. My initial thought was two fronts, two rears, center, sub, and a new 5.1 or 6.1 receiver. I'm starting to wonder instead if two bookshelves and a sub, along with new receiver will suffice. Maybe a center for television/DVD, too. I'm currently using a 24 year-old Marantz 38 amp receiver with two Boston Acoustics floor speakers. This is generally good for music, but not for DVD. Budget is under $1,000 for speakers and receiver. Any advice?

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