Pretty much every bottled BBQ sauce I've ever eaten tastes to me like a smoky form of molasses or brown sugar syrup. *blech* far too sweet for me.
My go to sauce for pulled pork is a South Carolina style mustard sauce. The recipe I use is:
4 parts mustard
2 parts vinegar
1 part honey
1 part brown sugar
few dashes hot sauce
S&P to taste
My hot sauce of choice is always Franks, and my "few dashes" ends up being "A lot of dashes".
Another sauce that I've really fallen in love with is the Apple City BBQ recipe that I got from the book, "Peace, Love, and BBQ" (absolutely FANTASTIC read if you've got any interest in BBQ, BTW). That recipe can be found at:
http://bbq.about.com/od/barbecuesaucerecipes/r/bl50617c.htm Those are the 2 sauces I always have on hand (although used the last of the mustard last night...eeek!) I really haven't felt the need to branch out much. One is a great semi-sweet tomato based, the other is a fantastic mustard based. Occasionally I'll make a NC style vinegar sauce, but those aren't my fave at all. Both of these are infinitely better than anything I've gotten out of a bottle.
Also if you want to play around with sauce recipes every sauce is pretty much a balance of tart (vinegar/mustard), sweet (brown sugar, honey, ketchup, jellies), and spice (chipotle, cayenne, hot sauce, etc). Other flavors that work well in sauces, IMO, are fruits (use a good jelly to add fruit and some sweetness). Obviously mustard & ketchup, but don't forget they'll add tang/sweet as well as their base flavors. Smoke is a good addition, but I really don't like liquid smoke. If I want smoke I'll use Chipotles for the heat component...or I'll do my sauce cooking on the grill to get some smoke flavor to it.
Sauce is fun, you can pretty much tweak and play with it how you like, and come up with something new and original! And if you don't like it, the ingredients are mostly pretty cheap! I've experimented with quite a few sauces, though, and the 2 above are my faves. I've worked on a raspberry chipotle in the past, and haven't quite got it hammered out to perfection...may need to retry that one again and tweak it some more
