Some of the very best bargains in home theater are found at online only electronics manufactures. Online only companies skip the middleman and pass the savings directly to you and in many cases they give you the most bang for the buck.
Some of these manufacturers started building products as a hobby and found enthusiastic 
buyers in home theater forums. After making a few and selling them it became apparent, a successful business could be created. This was the case with the first online only manufacturer I became aware of. SVS started out building cylinder style subwoofers with a perfect combination of punch, deep bass and accuracy that simply can’t be matched for the price. SVS has since added traditional subwoofer designs and front and rear speakers that are every bit as good as their first mind-blowing subwoofer.
The advantages of buying from one of these manufacturers is easy to see, the downside is you can’t walk into a brick and mortar to listen to their equipment. To address this they all offer amazing customer service and an easy return policy that protects you in the event you decide the product just isn’t for you.
You can find more information on any of these manufacturers on any home theater forum and if you ask nicely, it is pretty easy to find someone in your area happy to let you demo the product in their own system.
The next 
manufacturer I came across, who also has a loyal following was Outlaw Audio. Outlaw started building powerful, well-featured receivers at a great cost. They have since added amps, speakers and accessories that meet the original Outlaw vision of quality and performance at a great price.
When it comes to cables, there are a lot of opinions and most home theater enthusiasts believe price is the last factor in 
getting quality cables. An additional thought, one I agree with, is that Monster Cable is a huge rip-off. This is where I have really saved a lot of money while getting some of the very best cable made. Blue Jeans Cable builds hand made cables for every audio and video need using the highest quality parts. Blue Jeans Cable researches each cable carefully and offers clear choices based on your individual needs. These are in my opinion audiophile cables at basement bargain prices. Do yourself a favor and ignore the advice you get in the local store, go online and buy the best at a fraction of the cost.
Elemental Designs has been a well-known manufacturer in the custom car audio community for a long time, now they are
building a reputation for best bang for the buck home theater speakers and subwoofers. When I upgrade the speakers in my living room system, this is where I am going. Elemental Designs also has a big discount when buying packages and offers an easy to use tool that lets you build a custom system from 2.1 – 7.1. I have had the pleasure of setting up several of these systems up for friends and I love the sound of their speakers, especially for the money. One note on these speakers however, even the smallest bookshelf speaker they make is enormous, if size is a factor, measure carefully before ordering.
This brings us to our final online only manufacturer and these folks put power, lots of power, into 
your system. Emotiva builds big, heavy, powerful amps at unbelievable prices. Being the owner of the famously power hungry Magnepan speakers these amps make me drool like a dog watching the chicken coop. Emotiva amps are fully 4 ohm capable and push anywhere from 125 watts into 8 ohms to 500 watts into 8 ohms. Even more impressive is that they double or nearly double their watts into 4 ohms, which is an indicator of a well-built amp.
I am sure there are other quality online only electronics manufacturers out there and I would suggest giving them a chance. To find out more from people who own these products and will happily answer your questions with real world experience, check out Home Theater Forum and AV science Forums.