An apple or banana with peanut butter makes a really good pre-ride snack. I take the shot blocks that Knot mentioned with me when I ride. I don't always break into them, and it's extremely unusual that I'd eat the whole tube, but it keeps me from digging into the emergency gel. They also don't really melt.

Just water and those shot blocks are fine for most of rides. I take a bottle of diluted sports drink if I'm riding far and/or it's really hot. For the most part, it's just what I normally eat, but I'm starting to find I need protein in the hour or so after I get off the bike, or I'll be eating everything I can get my hands on and then some for the rest of the day.