If you want reasonable sound and all of the features you want from a complete pre-packaged all in one surround setup, you may end up spending a lot of money to get what you want. I think that you will find that people who really care about the sound quality AND want more features will end up buying a dedicated surround receiver/amplifier, and then buying components as required. A full system for someone who cares (but isn't some whacko who spends $10,000 on a single power cable) might include these items:
Receiver - contains a gazillion inputs, has all the hardware decoders (DTS, dolby digital, optical/coax, etc), and has outputs to either all the speakers (if the receiver has a high quality amp) or has only a pre-amp built in to reduce noise/crosstalk and has outputs to a dedicated amplifier instead.
Dedicated multi-channel amp - Expensive ones will have a whole separate daughterboard for each channel, with shielding and separate power between each channel. If you don't care to spend the $$$ for dedicated amps like this, you might as well get a receiver with a reasonably high power amp built in. JVC and Sony have some nice 300W+ output receivers for under $400, much less if you get the year-end closeout sale discontinued model. I have a nice sony receiver that was one of the last mid-range models to hit the streets before digital video cables became standard, so I got it for about 50% off when they went to the new models built to support HDTV. It still has the full audio features including DTS and dolby digital decoding, but it won't switch hdtv video sources and doesn't do the latest 7.1 ultra high def audio decoding from BD players. Don't care though, my TV has plenty of inputs and my living room isn't big enough for more than 5.1 speakers anyhow.
Optical player - Blue-Ray is what you need. The important things are to get a reasonably good quality unit (the cheapo ones on sale at wal-mart tend to overheat and freeze up in the middle of the movie) and to make sure the outputs match the inputs on your TV and receiver/decoder/amp. If your receiver will accept and decode the best quality sound, then the player just needs an optical or co-ax digital out to hook up to your receiver. If it doesn't though, then you need a BD player that does the full audio decoding and has 7.1 speaker outputs that will plug into your receiver or dedicated amp.
Speakers - You get what you pay for, generally. BOSE sounds ok some of the time, but a challenging soundtrack will highlight the limitations of the hardware and the BOSE systems tend to be expensive. Again, if you care about the sound quality you will need to read some reviews on quality units and buy matched speakers from the same manufacturer that are designed to work together. If you buy mis-matched speakers, you may have to do a lot of fiddling with the output levels for each speaker otherwise some will probably end being too loud or too quiet compared to the other speakers. Bigger isn't necessarily better, but a skinny tower full of tiny speakers will get you tiny speaker sound, no matter what the marketing pamphlet says.
Powered subwoofer - No doubt about it, you get what you pay for here. Do NOT get the $89 on sale Sony 10" from best buy or wherever is trying to dump them. Those pieces of crud will hum all the time due to really cheap circuitry. Yea they sound ok in a loud showroom with the volume turned way up, but trust me, they are terrible to live with. Go with a quality subwoofer with variable cutoff frequency and gain, but don't go too crazy. Subs under $250ish are in my experience generally horrible, but you have to spend well over $500 to get to the next true jump in quality (again, in my experience).
If you want to save some money on speakers, consider buying speaker kits. They contain all the parts to build your own speakers and you can often buy complete surround sets, then build and finish them to your own standards.
The other option is to get an HTPC and plug it into a "stupid" set of amplified surround speakers that don't do fancy decoding and have only one input. Make the PC do the decoding work and just push out audio and video to whatever speakers and TV you have.
