Champions:
Fighters that may either use one-handed weapons, or more preferably, gigantic "large weaponry," i.e. really big hammers, giant swords, etc. Their spells consist mainly of debuffs.
Thanes:
Fighters that may use almost any weapon, but most prefer hammers (most quest weapons for thanes are hammers, to go along with the Thor thing). Their spell line, stormcalling, is awesome - it is mainly damage-dealing (zapping enemies with lightning) and has a couple buffs. A thane is a great combo of a fighter and a direct damage-based caster.
That being said, someone may choose a champion over a thane because of the huge weapons, or because they like to debuff... but i see it as just realm preference. I think thanes own champions any day.
Edited, Thu Jul 1 13:37:24 2004 by Cailiem