Yosharian
Arcane
Bards are best kept pure.Uhh.. you wouldn't? Mixing two caster classes is a horrible idea, even if you went Mystic Theurge that would still suck because you'd only get the spells and not the class bonuses from Bard.How would you build a Bard/Crusader? It's a class concept that I find interesting.
Not to mention that you'd have two different casting ability scores, which would be a nightmare.
Also Crusader is just a shit archetype to begin with.
What about a Bard/Fighter or Bard/Paladin?
The best thing about Bards are the things that get better the more Bard levels you have. Which, honestly, is mostly Inspire Courage. Everything else is.. not that good.
Bards excel at Knowledge gathering and social activities, two things which tend to be very poorly implemented, if at all, in cRPGs. So you get them mainly for the buffs, and for the Inspire Courage.