Artorias, the most elite knight of all, unmatched with a greatsword..... at least, until i killed him with his own blade. In all seriousness, Artorias is the closest thing to the penetrator fight of this game- no tricks, just two warriors slugging it out, equal in their own respects.
I keep waiting for Aldous Huxley's ghost to show up and say " I told you So!"
I just beat Ornstein and Smough yesterday for the first time. It took 26 tries, upgrading equipment for about 3 hours and tons of cussing. However, it's been my favorite and most rewarding boss so far in Dark Souls. I'm really looking forward to 4 Kings and Kalameet, after I get the DLC.
However when you just start the game the fear of the Gargoyles I think surpasses it. The satisfaction you get from ringing the bell is monumental. That you actually accomplished something in a game thats not telling you what to do.