[Samoht]

The best class? There are a few default "lol no" answers:

Ranger
Magician
Druid
Necromancer

Then there's the best for what you want to do at any particular moment:

Raid tank: Warrior
Group tank: SK/Paladin
Healer: Cleric
Sustained DPS: Rogue/Monk
Burn DPS: Wizard
Puller: Monk/Bard
Support: Enchanter/Shaman

But, indeed, it goes a little deeper than that. Most lucrative tradeskiller? Shaman/Enchanter

Best PLer? Bard/Druid or Enchanter (Chardok style)

Best old world solo artist? Enchanter

Best Velious solo artist? Shaman (Iksar > Ogre)

Character that's going to cost you the most PP buying spells? Shaman.

You want to make a class that's in demand? Cleric

Want to play a class no one else wants to play? Pick any tank.

In the end, an Iksar Shaman is probably the best possible choice for what to play, but it's going to be a huge platsink. And if you actually do get Torpor and your DoTs, that's PP you will never be able to recover. But it might be worth it when you're soloing Lodizal and WW dragons.

There's only room for so many Shamans or Enchanters in a raid, though. Only room for so many tanks. Cleric comes back up for best raiding class. Pick Rogue/Monk/Wizard for best raid DPS.

It seems that the best class is really situational and subjective.