Chowhounds add a variety of things to their basic hummus recipes to change up the flavors. Some popular blend-ins are roasted red peppers, sun-dried tomatoes, roasted garlic, caramelized onions, green onions, parsley, and hot peppers. (Not all at once, of course!)
HillJ likes a really lemony hummus (she uses 1/2 cup lemon juice and 1/4 cup zest to 2 cups garbanzos) with a bit of parsley pureed in, and a dash of paprika and a handful of toasted pinenuts sprinkled on top.
2m8ohed makes hummus using edamame in place of garbanzos.