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I use THIS in my home office. Devices are HDMI to TV, sound is optical from TV to bar, plus I use bluetooth from phone to bar. I just realized the bar itself does not have HDMI in but I don't really need it. I like having the wireless sub and rear speakers because, well, no wires.
So, here's an ok option http://www.amazon.com/VIZIO-S3851w-D4-Wireless-Subwoofer-Satellite/dp/B00KUB3RGS/ref=sr_1_5?s=electronics&ie=UTF8&qid=1435167818&sr=1-5&keywords=wireless+home+theater
If you go this route, you won't have to worry about a receiver, but you're sacrificing some potential quality. There aren't many good wireless options, but the reviews on this model should tell you a lot. Like the other person said, you can hide wires by running them under the baseboards without doing any damage. If your whole setup budget is 2k I'd look into home theaters in a box. Those come with everything you'd need audio-wise.
I recently purchased this sound system. although refurbished as far as I can see (or hear the only issue is a minor scratch on the top of the sound bar. It has an optical cable option. I have absolutely loved it so far Vizio Speaker and Soundbar
As the other guy said, what you're looking for is a receiver. These things are not cheap (at least $200). It also doesn't really make sense to buy a new receiver and then hook up garage sale speakers to it (unless you know the speakers are top notch). That would be like buying a new car and then putting used tires on it.
Also, the ".1" in 5.1 stands for a sub woofer. Looking at least another $100 for some of the cheapest ones.
You have two other options if you don't want to go this route:
1)Home Theater in a Box (HTiB). This is basically the entire setup, 5 speakers, some sort of receiver/blu ray player and a sub. Usually start around $300.
2)Sound bar. Basically the same thing as an HTiB except the sound bar is the receiver+front+center speakers and there is no blu ray player. These things start at $200.
For either of these, you can hook them up however you want. For simplicity, I would say hook them up to the HDMI out on your TV, or optical out. Discussion on the difference here. This way you can have your DVD player hooked up to your TV and your TV will send the audio signal to the sound system. Some of the systems can also sync up with your TV remote, so turning the volume up/down with your TV remote works on the sound system. For more info on HTiB vs Sound bar here is an article.
It got some decent reviews on Amazon.
http://www.amazon.com/VIZIO-S3851w-D4-Wireless-Subwoofer-Satellite/dp/B00KUB3RGS
(was curious as I wouldn't mind a wireless setup for my downstairs TV, so took a look)