Zesty!
I recently moved to southern California, where avocados literally grow on trees. They are everywhere here, and often on sale, so I am much less reluctant to experiment with them than before.
The biggest key to guacamole is making sure that your avocados are ripe enough. The timing can be tricky here! If you need your avocados to ripen faster, put them in a paper bag. Adding a ripe banana to the bag will help them ripen even faster.
Guacamole is like salsa: it comes in a million different varieties. The basic ingredients are avocados, lime juice, minced onion, cilantro, and some heat - in whatever form and amount you like. If you are a spicy food enthusiast, mince up serrano or habanero peppers. Jalapeno peppers are a little more mild. You can also just use cumin and cayenne pepper, for the flavor without the heat.
Here are several different guacamole recipes you can try, and feel free to substitute for the ingredients you have on hand.