My recipe:
Avocados (obviously)
Diced heirloom tomatoes
Chopped shallots
A clove or two of garlic,
Cilantro (grown in back yard)
Lime juice (just a little)
Spicy chili peppers, chopped finely (grown in backyard)
GOOD tortilla chips, none of that tostitos shit.  They're good, but good guacamole deserves better.
I NEVER EVER put sour cream in my guac, I just think it completely ruins it.  I'm no fan of sour cream, ever.