Everything listed in this Database is taken directly from the NWN2 Toolset item lists. This Database contains all plot items, armor, weapons, books, jewelry, gems, etc for the Original Campaign. (If you are looking for the items from Mask of the Betrayer, look at the New Items (MotB) link.) The only things we left out of this database are creatures (monsters, NPCs) and creature items (bite1d4, etc). I've took the liberty of sorting the list while I was typing it up into more managable sections for easier referencing.
Update: The Item Database that Wandaien created has just been modified. There is a new page for all of the Special Edition Item sets and all of the lists have been reformatted and reorganized. But the major change is the addition of item locations to the lists. Not all items will have locations. In general, non-magical items will not have locations listed with the exception of items related to crafting and a few others. We expect to continue to update the list in the future. It's impossible to catch everything on a single walkthrough. Future updates will include merchants for scrolls and additional item locations.