Race Nutrition

I'm training for my first half IM, the Diamomndman in Bear, Delaware in the fall.  In the shorter tris I've pretty much relied upon water and a couple of energy bars during the race.  In preparing for this long distance tri I've experimented with gels (which do give me a boost) and fruit (dry and fresh sliced) which I.ve also find beneficial.  But I think I should plan on taking in more substantive snacks and calories to help avoid fatigue for a race that will see me out on the course for several hours.  What have you had success with consuming during a long tri -- pb sandwiches?  any meats?  I know easily digestible foods are preferred,  but I worry a bit that light fare will not give me enough fuel to sustain a prolonged race effort.