I have had great luck with the dial timers like harry mentioned but BOTH my coralife ones mentioned went bad on the timmer side which is funny since they are a simple dial timmer also....the timmer side just stopped working, naturally in the on function so now I have 2 very pricy power strips.
The dial ones from a hardware store run off a pin flipping a switch on and off to power the plug and its pretty hard to mess that up. Wonder why yours failed so ofen Wayne? I have had the super duper cheap 2 prong that I put an adapter on mess up but the ones with three prongs (appliance timmers about $10 each) all seem to hold up and do fine for me. Also you need to figure in the $10 added shipping charge from a online order. If all you were getting was a dial timmer you would be better off going to a local store.
Also, look for ones with little peggs kinda thing attatched that you pull all up for on and push all down for off you want to function. In other words, the little pegs that flip the switch are permentally attatched. They have some with little pegs that are not built on to the timer you put on the hours you want but I have 2 laying around because I have somehow lost all those tiny pegs! I pulled them out one day in the tank stand only to never be found again they are so tiny.