Healer.
I think Baldur's Gate is probably the game that defined alot of the tactics that I still use today. It was my first experience with D&D rules and also my first western style RPG, so I didn't really know what I was doing. I actually had a couple of false starts, where I created my character and within 4-5 hours I was getting totally owned and decided to re-roll.
First time I was a mage because I was thinking "yeah, fireballs, cool" but I was sooo weak in melee. Second time I was a warrior and I got further but was still dying alot. But having recruited Jaheira, I recognised how useful her healing spells were. So my next attempt that ended up being successful, I decided to go cleric, still recruit Jaheira, and effectively double my party's healing spells.
When I play Elder Scrolls, I try to build a very similar character - heavy armour, single handed weapon, shield, healing and a bit of destruction. Same with other RPGs as much as the ruleset will allow. In TF2 and Killing Floor I've played hundreds of hours as medic. In Xcom I try to bring 2 supports with upgraded medkits.
Basically my principle is: "I can't kill the bad guys if I'm dead, so stay alive as long as possible".