The "real" way to go would be:
Consular ---> Jedi Master / Sith Lord
Mean force powers and almost infinite force points, helll you won't even need your lightsabre.
Sentinel ---> Jedi Watchman / Sith Assasin
Well balanced character, this was my choice on my first playthrough. Kicks ass with both sabres and force powers.
Guardian ---> Jedi Weapon Master / Sith Marauder
Bad ass Meele-SoaB, you'll simply cut down anything that gets in your way.
The thing is though (as said) that the game is all to simple and no matter what classes you choose you will still be unstoppable after a few level-ups.