I helped them out, but after I found that they killed all the tennants, I destroyed them all.
My favorite quest has to be the Bigtown quest.
Though to be honest I've been spoiled by mods and a lot of my favorite quests are from those mods.
Actually, I loved the lovecraftian office building, but the name excapes me at the moment.
Finding that thing in the basement and killing the crazy ghoul was just cool.