Smough & Ornstein are the the only bosses (is the only boss?) that I really had trouble with. Seriously, took me around 12 hours to finally beat them on my first playthrough. I also never found Ceaseless Discharge that hard; beat him my second try on NG and my first on NG+. Apparently he has more attacks than just smacking his arm on the ground and leaving it there for ten seconds, but I've never seen any of them.
Also, on a related note, I can safely declare that Smough by himself is the easiest boss in the entire game (Pinwheel doesn't count as a boss). With Painting Guardian Sword +15 and 30 Dex he went down after, like, two full stamina bars of 2H's.
Unofficial "That guy" of darn near everything. Peaceful days died. Let's survive.