I was searching for solutions, just like you, about 1 1/2 years ago. My goal was to soundproof my entire basement since my theater, which is in my basement, is not a truly dedicated space. I used RSIC clips and hat track on the entire ceiling and decoupled all walls from the rest of the structure. I used double 5/8" sheet rock with greenglue between the layers. I built light boxes for all recessed lights and paid meticulous attention to sealing all holes, including outlets and switches. I have a separate HVAC zone for the basement, using a manifold and flex duct to isolate it from the main HVAC system. My doors are all exterior grade solid core with full seals and thresholds with automatic bottom drop seals.
There is nothing new in what I described above. I simply applied the techniques that I learned on this forum and from the GreenGlue and Pac International web sites.
While my basement is not yet completely finished, all of the "soundproofing" features are in place. I have to say that I am amazed at how well my basement is isolated from the rest of the house. I can crank up my sound system to uncomfortably loud levels, and it is barely audible in the rest of the house.
It seems that people always want a shortcut, easy or cheap method to achieve good sound isolation. If you really want to have good sound isolation, use the principles and products described on this forum. They work. Don't take any shortcuts or use cheaper alternatives.
Read the big Green Glue thread
. Brian has shared a wealth of information on sound isolation principles and practical implementation guidelines. Sure, it is an investment in time to read the whole thread, but you will learn most all of the knowledge you need for good sound isolation.