Sound Dampening - Where to Stick It?

I know a few of you have experimented with applying sound damping materials to your Taco (i.e. Dynamat).

I have a few questions:
1. What type of material/company did you use?
2. Do you think it was worth it?
3. Where did you apply it?
4. If you had to do it again, what areas would you skip?

Cheers...

 

I covered the underneath of the console cupholder as well as the bottom of the armrest storage container (pull up the little carpet square first)

 

I'd put it on my butt, especially after chili and beer on Monday night at the bar.