To an extent, I've always had a certain notion of a party leader for my groups over the years. Charismatic, wise , strong and somewhat clever. Generally speaking, a roll of 100+, if that analogy suits you better.
And usually I've always fitted a Paladin into that category, seeing that many of those qualities fit that class perfectly, but lately I've digressed from that notion a bit. I figure, pragmatically, that a plain Fighter, Mage, Cleric, Thief or whatever could do just as well.
But how do you pick the face of the group? Stat-based, some notion of leadership by class, powergaming or is it a little more vague? Roleplaying qualities like "(S)He's the leader, and the class and stats are largely irrelevant, because that's the RP-stuff I do"?
I always picked a Paladin to lead my IWD-parties, but usually because the Holy Avenger just seemed to good to pass up. Not so much because of the class abilities, even though they're largely nice to have. I've started to wonder if that's really worth it.