First off, Jan. His stories are damn great. He has excellent interaction with other characters. Him and Korgan get along fairly well too
However, he is also an incredibly utility character. He is great for finding, disarming, and setting traps. He is also great for debuff the mages. Can you say time stop trap?
Breach, Ruby Ray of reversal, send in Korgan and Sarevok and a few hits and you have a gibbed mage
Not to mention he can do some good damage with Firetooth, and its upgrade, since he is proficient with x-bow.
Secondly, Haer'Dalis. I think he makes this game LESS aggrevating. Once he gets to 3 million, take the Enhanced Bard song and have him sing the rest of the game. +4THAC0, +4 Damage, immune to all sorts of nasty effects, and give him - 10 AC as well. How can you afford not to have him in your party!
There you have it. A tribute to two great characters, who usually get overlooked.
Cheers
G