After owning this game for forever but not making any significant progress on it, I'm gonna try and actually play through the OC and expansion campaigns. I checked out the Ultimate Link List thread but the sheer amount of stuff is kind of overwhelming to me. Are there any bugfixes or other things I should definitely download (like the patches for Baldur's Gate and Planescape: Torment that restored all the cut content) for this game? I'm not interested in graphical updates as much, as my computer is pretty outdated.

My non-expert answer is "not really." From what I can tell, it's not like Oblivion/Fallout/Baldur's Gate/etc., where community patches and tweaks significantly enhance (without changing) the vanilla campaigns.

There are two things(from this list) that I think are recommendable:

1. Familiar and companion fixes.
2. Transparent GUI (even this is debatable. The default GUI is fine, and this throws in an annoying splash screen when you load the game).

I haven't tried the other graphics mods because I'm on an old PC with integrated graphics.

EDIT: Might I also suggest the fast rest override? It makes you rest a lot faster (might be considered cheating, but watching a progress bar fill is hardly a valid part of gameplay). Really helpful if you're a class like Wizard and are always resting.

http://nwvault.ign.com/View.php?view=Other.Detail&id=1240