I haven't read every entry, so please pardon if this is already covered or obvious to all... but one secret to good dry rub is to mash in the powder mix, and then WRAP TIGHTLY WITH PLASTIC WRAP and shove in fridge for several hours. Basically a dry rub marinade, to impregnate the meat.
Not having had my butt rubbed, my homemade mix sounds a lot like skier219's... blend of sweet and hot, with chili powder, paprika, brown sugar, pepper, mustard, anything else I grab. But no salt... enough of that in the smoke.
I have used both smoker (simple Brinkmann two-level cannister, charcoal with water-logged mesquite chips, make sure water pan in place between meat and heat... 4-6 hours for ribs or turkey breast) and gas grill (light burner(s) on one side, stack ribs on the other... 2-3 hours). The latter leaves it juicier, the smoker tends to dry out a bit more (logically enough)... and yes, you can count on throwing away... or at least washing... your clothes!
Lately we've been smoking lots of beef jerky. Flank or other steak without lots of marbeling veins, sliced 1/8" to 1/4" thick, wet marinade overnight, only takes 1-2 hours. Better than storebought!