As the others above have commented, we don't know your level of heat comfort, so everything is just a guess hoping to hit the mark. The other side of the coin is your personal tastes and likes. There are sauces with all different types of bases to start with: Vinegar Base, Mustard Base, Catsup Based, and Tomato based to name a few.
Also a spicy rub can had a spicy layer of flavor under the sauce. I'd suggest Oakridge Habenero Death Dust, spicy, but not a killer hot.
If you are looking for mild heat I'd suggest "Craig's BBQ Sauce" from Pepper Jelly Inc. Slightly sweet and tickles your taste buds with mild heat.
If you want something spicy for chicken I'd suggest "Boss Sauce (hot)" or "Sal's Sassy Sauce (hot)". While it has a mustard base, it also has some sweetness and some citrus to balance out the mustard and the heat. They are my favorite chicken wing sauces, and they are great on grilled pork chops as well.
For beef and pork, I'd suggest Head Country Hot BBQ sauce. A little thinner, which is great for beef so that you don't have that sweet thick sticky layer of sauce sitting on top. You can also thin any sauce with a little apple juice or cider vinegar depending upon your personal tastes or preferences.
The BBQ-Brethren also has a sauce review thread that list some characteristics of some of the many commercial sauces available. Feel free to browse some of the results.
http://www.bbq-brethren.com/forum/showthread.php?t=14889
Good luck in your search....