Deltronics in Woodridge, IL has been excellent at fixing several different components for me over the years. They always get it done right. They also tell me whether it's worth doing and discourage me from having it repaired if it isn't.
Modwright has been over the top great in repairing or replacing my CD player, even if I didn't buy their player originally from them. Dan always want the customer to be happy in the end.
Paradigm speakers has also been very good to replace blown drivers at no charge other than shipping one way.