In ME1: Soldier. Regenerating Health, and skill in every weapon, as well as heavy armour is really helpful. Since I was the only one that needed to stay alive, this was a must. I let my squad do all the casting - under my command of course.
ME2 and ME3: Vanguard. Charge, and Charge and Nova, were just far too fun to take assured life over them. In ME3 I was able to charge once every 2 seconds, restore half my shield in doing so, and 25% of the time charge twice in a row instantly. My fights didn't use guns. I was the projectile, and the enemies never stood a chance.
In ME2 its a fair bit harder as the Vanguard, and requires more careful charging, but in ME3... Carrying just a shotgun with Frag Rounds, I was literally a Biotic Wrecking Ball.
ME2 and ME3: Vanguard. Charge, and Charge and Nova, were just far too fun to take assured life over them. In ME3 I was able to charge once every 2 seconds, restore half my shield in doing so, and 25% of the time charge twice in a row instantly. My fights didn't use guns. I was the projectile, and the enemies never stood a chance.
In ME2 its a fair bit harder as the Vanguard, and requires more careful charging, but in ME3... Carrying just a shotgun with Frag Rounds, I was literally a Biotic Wrecking Ball.