Well, toons, of course, depend on what play style you like. Hero side, they are:
-Scrapper: Easiest to jump in. Pretty good 1 on 1 damage with some melee range AoE attacks and fairly good defensive skills. The usual Scrapper strategy is to jump in the thickest part of the fight and hit people until there are none left.
-Tanker: Like the name says, the tanker specialises in being ridiculously tough and has some pretty good taunt power. A tanker fights melee, but does a lot less damage than a scrapper.
-Blaster: One of my favourite archetypes, the blaster is all about raw offensive power. The downside is that the blaster has very few defensive powers so the usual blaster strategy is to kill before you get killed.
-Controller: My other favourite archetype, the controller specialises in status effects. Pretty much all offensive controller powers also immobilise, hold, cause sleep, confuse or knock around the enemies. The big downside of controllers, aside from being squishies like the blaster, is that bosses tend to be resistant to their powers, so you have to stack effects.
-Defender: Unlike what a surprisingly large ammount of people think, Defenders don't mean Healers. In fact, only one powerset specialises in that. Defenders specialise in buffs and debuffs and this is one of the archetypes with the most variation between powersets. This is the powerset I've played least so I can't give much more information.
-Scrapper: Easiest to jump in. Pretty good 1 on 1 damage with some melee range AoE attacks and fairly good defensive skills. The usual Scrapper strategy is to jump in the thickest part of the fight and hit people until there are none left.
-Tanker: Like the name says, the tanker specialises in being ridiculously tough and has some pretty good taunt power. A tanker fights melee, but does a lot less damage than a scrapper.
-Blaster: One of my favourite archetypes, the blaster is all about raw offensive power. The downside is that the blaster has very few defensive powers so the usual blaster strategy is to kill before you get killed.
-Controller: My other favourite archetype, the controller specialises in status effects. Pretty much all offensive controller powers also immobilise, hold, cause sleep, confuse or knock around the enemies. The big downside of controllers, aside from being squishies like the blaster, is that bosses tend to be resistant to their powers, so you have to stack effects.
-Defender: Unlike what a surprisingly large ammount of people think, Defenders don't mean Healers. In fact, only one powerset specialises in that. Defenders specialise in buffs and debuffs and this is one of the archetypes with the most variation between powersets. This is the powerset I've played least so I can't give much more information.