I read in a walkthru that random item drops sometimes occurred in Undersigil, including some very powerful magic items (Bell's Shield and Ring Zero). I was just wondering if anyone had been able to find any items of interest down there (I once managed to find an Aegis Of Torment on the body of a Glabrezu) and, if so, what they were?

You can get useful stuff down there?

Fiddlesticks! I used to walk down there, fight until the Nameless One died, then go down again...never made it very far in, but I spent a good deal of time doing that, because I was SURE there was something useful to discover down there. I ended up just running everyone through the whole place, opening doors and such. ("Is that a hairless MOOSE? RUN!!")

I may reinstall that game just to go down there and get stuff...nah. "Getting stuff" was never really the point of PT anyway.

Hehe...hairless moose.
I think the best way to accquire useful items is simply to scout ahead with Annah and nick stuff from the shelves with her.
Is it me, or are those worm things THE single most annoying creatures in the game?
(And the most disturbing- just look at those mouths...)
There are a few non-random things you can find down there anyway (on the shelves/in containers)-
'Shackles of Light'- Invokes 'Chain Lightning Storm'
'Crimson Sphere Earring'- Protection against fire (useful against Ignus)
I think there was something else as well, but my memory escapes me.

It's true.

After you return from Curst down there you'll find Greater Glabrezu almost each time you reenter the area. When you kill him, it most times drops money, but on rare occasions he drops those five nifty items:

Aegis of Torment
Bell's shield
Heaven and Earth (club)
Ring Zero
Umei Kaihen (fist weapons)

You'll have to kill many of them to put your claws on those items.