Please forgive me as I'm sure it's been done before but let me just chime in with mine so far: The Harpy Cave in TOL. Thankfully my fellow gamers came to my aid. I haven't even finished the game yet but after getting this far, it was by far my toughest fight. I would even venture to say that's true for the BG series also. It was extremely frustrating the first 10 time or so (yeah-it's true!) and gratifying beyond belief when that last one fell!!!

Anyone else have a tough one?

The last battle of HOW was by far the most difficult for me. I kept coming back to this board for tips, but for some reason, none of them worked for me! Stupid luck... I eventually beat it by setting the difficulty setting to "easy," but I consider that near cheating. Am highly considering going back to do this battle again under normal difficulty.

Last battle on HoF mode, very tough, They toss in two demons that come from the portal as well as having to handle Iron Goloms with twice the hit points.

My 2 cents:

Yxunomei. Playing HoF AND never having fought her before (without tips, hints, or cheats). She invites those magic snakes behind you when she changes into her snaky form. I kept wondering why the hell my Mage (in the back) was screaming so much!

Ahh, so the worst (or best?) is yet to come...

The Harpy Queen in HOF mode, the NE corner of the Keep in TOL, was so hard that I actually turned off HOF mode just for that battle. The cut scene is what stuffs you up. Without that it would have been possible to defeat her in HOF.