Can someone recommend some sound deadening material?

I used Peel/Seal as well as a sound deadener kit similar to this (see pic):

http://www.ebay.com/itm/Under-Carpe...Parts_Accessories&vxp=mtr&hash=item4162d897d1

Just be sure to leave it in the sun for a while and it forms to floorboard really well.

I personally feel the Peel/Seal helps more with heat and some sound... but the thicker sound deadener pad is the bomb. I also had mass backing on my carpet... may be overkill but its down and Im happy. Thats all that matters.

Heres another link:
http://www.forabodiesonly.com/mopar/showthread.php?t=91019&page=2