Store-bought vinegars are great, but infusing your own offers the double benefit of creating interesting flavor combinations as well as making something lasting and useful out of assorted leafy scraps that might otherwise go in the trash. Start with a quality white wine vinegar or white distilled vinegar, which absorb flavor well. Warm the base vinegar and add whatever herbs or stems or curious spices you've got on hand. Bottle it up and wait a week before using so that the flavors have time to meld and become pronounced. Be creative.
A few suggestions: Vinegar infused with arbol chili, garlic and a few sprigs of thyme (great on grilled items and smoked and grilled meat); lemon peel and thyme (perfect for a vinaigrette or add a bit of crème fraîche for a tangy, creamy sauce for roast chicken); burnt cinnamon-orange-rosemary vinegar (mix a spoonful with honey and drizzle over desserts for a sweet, smoky finish with just the right amount of acidity).