I haven't been to Plan B yet but I've been many times with my coworkers to Prime 16 (apparently they have good veggie burgers too). I love the Cowboy burger with a fried egg. I heard the owner opened a new place that specializes in meatballs (?), on Chapel across from the new Rudy's (which is now somewhat upscale and has quite good food too).
His new place is called the Meatball House. It's a good food concept, with four different meatballs (beef, pork, chicken, veggie) plus one daily special, and you can order them a variety of ways, i.e., over some great sides (people rave about the black garlic mashed potatoes and the mac and cheese, but my favorite sides are the kale and quinoa), on a roll, with one of four different sauces, or over a salad (also a favorite, especially the arugula). They also have a few different small pizzas. Like Prime, he has a decent beer selection at the new place, as well as some decent wines. BTW, he also owns C.O. Jones.
Rudy's is another that deserves mention. It's not the Rudy's we grew up with, but the new place is nice, and the Belgian frites and dipping sauces are still the best in the state imo.