Soldato
Also can someone give me some basic tactics, so I don't die straight away even on easy. I'm still at the tower part, where the big LOTR style battle has just started. I'm still on the first level of the tower. I have Alistair, a random mage and a random tower guard in my party.
Also, get used to each character and use them in a particular order. For example at the stage of the game you're in, throw Alastair into combat first (unless you're a tank yourself), then position yourself where you're most useful (mage - nearby, but not between alastair and more enemies; Rogue - in the thick of it, but move yourself behind the enemies so you're taking less damage and get the backstab bonus; Dog - with alastair, but try not to get aggro)
Aggro is "attention" of enemies. IE, a tank is best to get all the aggro, meaning all teh enemies are attacking that one guy, and everyone else can then attack the enemies without being hurt. If someone "steals aggro", then they've attracted too much attention (through high burst damage usually) and the enemy turns to attack that guy instead.