I think I would be a Summoner, as I'd prefer to rely on my summons rather than attack head on, and possibly with the white magic to keep my friends fighting fit in battle!

Perhaps a Beastmaster and I could capture monsters and train them, that would be fun!!

If I had to be a physical class then I've always liked the Dragoon class as I like spears and lances.

As for archetypes I think I'd be a mixture of Tifa with the serious and loyal side with some of Selphie/Rikku's unpredictability thrown in too!