Light Side. Though I've never went total light side. My character was a jackass when the situation warranted it (Like explaining in great detail how you will kill a group of Sith punks who are bothering you, or whenever talking with HK-47), but I generally went with light side.
My only gripe is that at the end of KotOR 1, you can't
tell the Jedi Council Asshats to shove their medal up their brainwashing asses while still rejecting the dark side. But other than that.
[begin munchkin nerd rant]
Oh, and Lightside doesn't get good powers? My Jedi Watchman had the Force Valor, Speed, and Aura powers maxed, with dual lightsabers modded out the ass. When I got Force Enlightenment (which is a spell that casts all three of those powers) at the beginning of the endgame, my guy raped all. Speed gives 2 extra attacks per round, and Valor and Aura buff your stats through the roof. So every round, I was getting 4 critical hits worth about 200-300 damage each. I also had force jump, which multiplies your attack power against enemies more than 15 meters away. I killed the giant storm beast on Malachor in 2 rounds, and didn't take any damage. If KotOR 2 had PvP, I would destroy >
I also had a high charisma stat, so casting Master Heal completely filled my life bar, and stasis rarely failed.
And my guy also knew Force Lightning. By the end, I had so many Force Points, the extra alignment cost was nothing.