Old thread but I'll lend my bits for the sake of good eats.
If you're going to BBQ(Low n Slow) I've learned over the years that I can buy better than I can make and have tried quite a few. Some of my favorites are:
http://shop.homebbq.com/
He has alot of different rubs and spices and I use the RibRub on all my pork. Butts, Ribs mainly. Beef Rub is pretty good on Brisket.
http://www.plowboysbbq.com/
He was the recent winner of the American Royal his stuff is also great. I actually will use his Bovine Bold when I grill chicken wings. The wife loves them so much I'm not allowed to cook wings without it. After this past Christmas, they actually started selling it in the Bass Pro Shops stores.
I've known both of these guys for a few years and they're good people. I know alot of professional BBQ'ers and many of them actually go by my rule(actually I guess I went by there's) and buy more often than make.
If you're doing a basic roast, I have always loved plain old Adobo seasoning on the pork roast. rub it on, let it set for awhile and place it in the oven to roast.
With all my meats, whether I BBQ or grill/roast/cook, I always use a slather of some kind. Some people like to use plain mustard, some use squeeze margarine, some use Oils. My favorite is Extra Virgin Olive Oil. It doesn't have to be high end high dollar stuff. Buy it in bulk. Rub the oil on the meat first to act as a binding agent to help hold the rubs/seasonings on the meat while it's cooking. Also, with the meat, I like to inject prior to cooking. I will mix the rubs with juice. With Pork, I like to use Peach juice(nectar) and blend in a little of the rub. It helps to flavor the meat inside as it cooks . I do the same with Brisket but use Beef Broth instead. I haven't injected the Adobo as I think it would overpower the flavor of the meat. I heavy outside coating always seems to do the job.