Prometheus
Prometheus was the wisest Titan. His name means "forethought" and he was able to foretell the future. He was the son of Iapetus. When Zeus revolted against Cronus Prometheus deserted the other Titans and fought on Zeus side.
By some accounts he and his brother Epimetheus were delegated by Zeus to create man. In all accounts, Prometheus is known as the protector and benefactor of man. He gave mankind a number of gifts including fire. He also tricked Zeus into allowing man to keep the best part of the animals sacrificed to the gods and to give the gods the worst parts.
For this Zeus punished Prometheus by having him chained to a rock with an eagle tearing at his liver. He was to be left there for all eternity or until he agreed to disclose to Zeus which of Zeus children would try to replace him. Hercules eventually rescued him without giving in to Zeus.
Epimetheus
Epimetheus was a stupid Titan, whose name means "afterthought". He was the son of Iapetus. In some accounts he is delegated, along with his brother Prometheus by Zeus to create mankind. He also accepted the gift of Pandora from Zeus, which lead to the introduction of evil into the world.
Atlas
Since the Titan Cronus was too old, Atlas led the other Titans in their ten-year battle against Zeus, which is called the Titanomachy. After the gods won, Zeus singled Atlas out for punishment, by making him carry the heavens on his shoulders. Most of the Titans were confined to Tartarus.
Gaea-Uranus-Cronos-Rhea
Oceanus-Mnemosyne-Phoebe
Prometheus-Epimetheus-Atlas