I have a 76 vette and want to have a more aggressive tone than stock.  I don't want loud and obnoxious or interior noise at cruising speeds.  So far what I've read from forums is that the ravin mufflers would give me the growl I want without the things I don't.  They're now discontinued.  Any options out there to be recommended?  

I'd suggest looking at Flowmaster or Dynomax.  

From what I've heard both Flowmaster and Dynomax are louder than I want, and have heard that both create a lot of interior noise.  

One thing that probably wouldn't be abad idea no matter what exhaust you use is some of the sound mat material form Custom Auto Sound.  I've seen it in action, and it works really well.

I think the best thing you're gonna be able to do is try and hear a car with the exhaust systems you're looking at, and decide which one you like best. Also remember that most manufacturers have levels of mufflers depedning on how loud you want the exhaust to be.