Four hours of morning light isn't enough sun for full-sun plants. Plants labeled for part sun would be the most likely to do well where you described. A mix of plants usually provides more interest for a container of significant size.
Some that should provide some "Wow:"
New Guinea Impatiens
New Guinea Impatiens (Impatiens hawkeri)
Plectranthus 'Mona Lavender'
Spur Flower (Plectranthus Mona Lavender)
Fuchsias
Fuchsias (Fuchsia)
Coleus are often so pretty, people don't notice there's no flowers,
Coleus (Coleus scutellarioides)
along with:
Many diff sweet potato vines
http://garden.org/plants/searc...
Tradescantia zebrina (wandering Jew)
Inch Plant (Tradescantia zebrina)
Caladium
Caladiums (Caladium)
Cane (angel wing, dragon wing) or wax Begonias, some flower more readily than others. Choosing ones with gorgeous leaves makes the flowers a moot point, in my eye.
Begonias (Begonia)
