I love the interesting kick an unusual condiment gives to sandwiches or to marinate meat, etc. (Unusual may be usual for chowhounds, though :)
Stuff like Tapenade, Roasted Pepper Aioli, Fig Chutney, etc. or things from Lulu's store (in SF).
I'm always looking for more interesting condiments or salsas and good combos. Can you post some of your favorites, recipes, sources, etc.?