Yeah, that's one of the other reasons I tend to use "stuff under discussion + core" - unfamiliarity.
Oh, and something I forgot to put on my earlier list:
6) Avoid overlapping abilities.
It's a bad idea to have a Fighter/Barbarian. You don't gain much vs. either. Both have full BAB, both have a good Fort save with poor Ref and Will saves, both have high HD. You end up with a literate Barbarian with bonus feats (and heavy armor / Tower Shield proficiency, but that doesn't exactly help). You're liable to be better off with a Barbarian/cleric or Barbarian/druid - the spells are liable to fill in for the feats very well (Divine Favor, for instance, keeps pace very well with the fighter feats that increase your to-hit/damage; Flame Strike can sub for Whirlwind Attack - at range, even - and so on), add some extra flexibility (healing, utility spells), and save on equipment (Magic Vestments and Greater Magic Weapon last all day fairly readily) - and you get a good Will save out of it, too.