Bruce,
It depends on what sort of angling experience you seek and what type of person you are. If, like Gfen, you're not a morning person then the answer is obvious.
I think for many trout fishermen, the evening is best due to insect hatch activity. Personally, I'm not a great fan of hatch matching and like to fish for species other than trout such as river smallmouths or surf stripers. In those cases, I like early morning. It's a peaceful time of day with little traffic or human activity and game fish are often very active whereas in the evening they're still recovering from boating and fishing pressure.