My personal view is that humour definitely needs to be a part of this game. Without humour, I find a gaming experience to be severely impacted. Of course, going by the primary yardstick I'm using for this project, Baldur's Gate I and II, the humour there was just right, to me. We had a comic NPC who had his necessary bouts of seriousness, making him not feel out of place yet becoming utterly unforgettable. Thank you Minsc. We also had the occasional quest or NPC that was laugh out loud funny (the guy wanting to commit suicide in BG1, or the Beholder in the Sahuagin (sp?) City in BG2 are good examples here. Finally, there are the items that have a hilarious description or sometimes even amusing impact on gameplay. See Lilalcor, the two-handed sword.
Baldur's Gate can, in no way, be described as a rollercoaster ride of comedy and satire, but these humorous moments made the experience come to life for me much more, giving a sometimes much-needed break from the seriousness of the story, and making the world seem like a world that much more.
Those are, of course my two cents.
Also, hi, I'm new here. Does Obsidian have a 'new guys' topic somewhere?