Which company has the best 5.1 surround sound speakers quality?

Sorry but there is no valid answer to your question. Sound is subjective, and how good it is with any set of speakers will vary with the music type (voice, baroque, jazz, rock, etc). There are hundreds of companies making quality speakers ... how would you ever choose the best? And even if you did it's probably going to be more $$ than you can afford. Also note that sound is not simply the speakers, it is the amplifier, the source and the room. And purists would claim it's also the wiring, the power conditioner ... even the power cord to the amp! A more reasonable question would be something like ... "For under $1000 what is the best value for a 5.1 surround sound speaker system consisting of tower front speakers, bookshelf surrounds and an 8" powered subwoofer to be driven by a model XYZ A/V receiver?" OK it's a bit long winded and you may not know all the details, but try again with some detail of what you want, your budget and what you would use them with/for. Any answers you get will simply be the respondent's current favorite ... essentially worthless input (unless you want to simply copy someone else with taste you don't know).

This is like asking 'whats the best flavor of ice cream?'. You will get lots of responses, all correct and all wrong. Speakers have flavor. You really dont want all the equipment from 1 company. Some are strong in some areas and weak in others. If it was me, here is what I would get: SUBWOOFER: SVS Cylinder series. Very well respected subwoofers at internet prices. HSU Research is also well respected. SPEAKERS: Paradigm is a very respected name. As is Definitive Technology, Energy and even Polk. RECEIVER: The $500 to $800 Yamaha or Dennon models pack a lot of features. DVD PLAYER: The Toshiba HD-A3 is a High Def DVD player selling for $199 this weekend. If I wanted to go BluRay, I would get a PS3 because it is actually one of the better performing BluRay players available. SPEAKER WIRE: Good 12 ga speaker wire can be bought by the spool from Parts Expresss. I would use it everywhere CABLES & INTERCONNECTS: BlueJeans is my favorite. They sell industrial wires to consumers for really good prices. My HDMI cable ran me $38 and works great. NOTE Remember that part of this hobby is 'ANTICIPATION'. You could buy everything I suggested and have a great system. But part of the fun is doing research, running out to audition speakers, Joining fourms to ask questions, etc. Dont cheat yourself of this fun by trying to buy an "all in one" system.

Sound quality is very subjective and price is a huge factor. Depending on what your budget is, you can decide from there. Personally, AV123 has a great special right now to check out for about $1k. http://www.av123forum.com/showthread.php?t=24756

BOSE are known for having the BEST sound quality and sound distribution If you can afford it its what you should get.

I LOVE my Bose.