Years ago I started off with Grub Rub and then found a much better flavor by mixing equal parts of Grub Rub and Fiesta Brisket Rub. It is probably the best balance of sugar/salt and spices you can get and usually find at most stores.
I got tired of spending so much on rub so I decided to start making my own and very happy with the results and usually make 6-10 lb batches and vac seal them, and give 1lb packages to family and friends.
Just experiment around you may be very suprised at how something tastes before its slow smoked to after its been on the pit for 14-18 hours.
thyme, mustard, cumin, celery or whatever on top of a base of sugar, salt, pepper, paprika just dont go too crazy you want your Q tasting better than the other guys but not like a pack of jolly ranchers!