Big fan of Willingham's esp used in conjunction with his marinade in his book.
Corky's is the typical Memphis rub and it adds a wonderful subtle taste to all things Q.
My absolute favorite is the rub from the Rendezvous in Memphis - can be bought over internet and I was actually able to clone with help from an old article in Memphis magazine. Has a lot of interesting spices including paprika, oregano, cloves, mustard seed, etc - interesting Greek undertones.