I think corn muffins and baked potatoes and chili are all very dense, and even with the veggie tray, it'd be nice to have a light, tossed salad with dressing options (which people could then put on potatoes, too.
My favorite potato is veggie chili (a must if inviting vegetarians) and cheese, or butter, salsa and black beans. I never keep sour cream around, but it's a wise addition to either.