I went through a phase where I was obsessed with Red Robin because they have some 50 different kinds of burgers, with interesting things in them, and they're basically all available in veggie form. I haven't had it since I left Detroit, though.
Red Robin FTW. You cant beat bottomless fries and their burgers are pretty big for the price.
In N' Out is best for fast burgers.
One of the better burgers I had was a Kobe burger made at home. I love burgers!