Which class is the most powerful/useful in Mass Effect 1? [closed]

This question is somewhat moot. All classes are equally effective in their own right and since it is a squad based game any shortages that your character may have can easily be augmented with other squad members.

Now as others have mentioned the Biotic (and the Tech) may indeed feel like support classes in ME1, especially at the begining of the game. But by the end they can all lay down the pain in equal parts (through better equipment and assigned talent points).

If you are seriously concerned about only having a pistol (which would seem odd if you are used to playing mage classes) you can do as yx01 suggested and play through as a Soldier one time and get the requisite kills with each weapon which will unlock those weapons for future, new Shepards in the form of a single bonus talent at character creation.

Keep in mind too that if you intend to import this character (or any) into ME2 that you are able to change their class shortly into the game if you desire (which seems somewhat contrary to the plot, but whatever) and in ME2 both the Biotic and Tech classes definately come into their own thanks to combos and some new talents.

So in the end the choice is really yours and depends on what style you prefer when playing squad-based third-person shooter RPGs.

I played through with a Biotic and the abilities get noticably better with upgrades - however you're never really a counterpart of a firemage, you're still mostly a support.

For example you get the ability to raise in the air the whole room of oponents or to pull them into black hole, but still you need your companions to actually shoot them. So you won't be throwing fireballs around in this game as a biotic, but you still get pretty powerful with disabling spells until end of the game.

The trick with the biotic in ME1 is that it requires you to:

1. Play through the game with another class to unlock a better weapon (i.e. get 150 kills with the soldier to unlock assault rifles).
2. Get a really high end biotool, like the Savant X, which drastically reduces cooldown duration and boosts power of your biotics.
3. Be at very late game unless you level up a lot to get good skills up faster.

If done properly, the biotic is extremely overpowered in ME1, by the end of the game, my biotic had a permanent barrier (it recharges before it wears off/gets removed), can sling singularity and lift all over the place, and shoot anything I need to kill with an assault rifle. Between singularity, lift, and stasis (I went with the Bastion class), I was able to kill the final boss without it taking a single shot at me, which made it kind of boring :)

Some skills to focus on which comes very handy is push and lift, push enemies off of ledges and lift will keep them helpless.