who's the best Holmes has ever matched wits against?

Hello everyone! I'm a Holmes fan too for as long as I can remember and I stumbled upon this site a while ago and well, Ive been itching to share some thoughts on Holmes with fellow holmes fans and its about time we got cracking!
So who do you guys think has been Holme's most worthy adversary (apart from Moriarty and Ms Adler of course-lets just leave these two out to make it more interesting shall we?).