Continuing the response from the previous post->
Well, priest actually. From what I've seen the other priest classes (druid and shaman) are actually pretty capable healers as well. It isn't like EQ1 where the cleric is the one and only true healer...
Fighter types are also a good bet. A party that intends to be effective really needs someone who take a decent hit and keep the mobs from running around squashing important people like the healers.
Mage types are also a good bet. They range from doing massive damage, to making the enemies fall asleep. The only class I've really been annoyed with so far is in this group however. The summoner (who eventually branches off to conjurer or necromancer) really sucked IMO, the pet was pathetic and the nukes will middle range. But that gripe is for another thread, and who knows.. maybe they worked on it some.
Scouts are also excellent, they have a good number of buffs and the ability to remove traps for treasure chests, which can cause some downtime (massive injury, debuffs, or death) if you get hit by a trap everytime you try to check for that yummy loot in the goody box.
All the classes get a good selection of buffs that they can place on their party members. IMHO they did a good job of making a game where all classes may not be equal, but all classes do have a role and are useful at it.