Two standbys are Detour Bars and Clif bars. The only problem with any of the products with chocolate coating is the coating melting and making a mess. So, Detour is better pre-ride.
I've tried several of the bars like Snickers but the ingredient list compared to the price made them some very expensive candy bars.
Hummm...Twinkies...One hasn't lived until you've had Deep Fried Twinkies!