Sorry, but too much forehead; maybe she and Marcia Cross could get together and form a society for women with mutant foreheads?

XD
Plus, to me, Christina Ricci is just too much of a human anime character.  She can do the "strange, mysterious woman" thing great, and she's got the Goth cred, but she's just too fragile-looking to be a believable Murphy.  Murphy's tough.   She's a cop and a martial artist. 
Sarah Michelle Geller...maybe.  She's a bit too waifish, too, in my book.  It worked on Buffy because of the dichotomy between the "saviour of the world" and the "tiny blonde girl."  But Murphy's supposed to be what keeps the Dresdenverse grounded in the real world.  She's a vanilla human, so if an actress has to kick butt like Murphy, she's gotta have some muscle mass to her.  You couldn't just explain it away by saying she has superpowers or whatever.

Christina Ricci would be a good choice for Esmeralda Batista, the vampire assassin from Changes, though. 

It's been said several times already, so I'll just throw my vote into the pile and say that I believe that Butters should be played by Zack Gallaphinacas.  The more he ages, the more he becomes Butters to me.

That's the guy from The Hangover, right?  Wasn't Butters described as short and skinny?  Personally, I've been seeing Simon Helburg in my head whenever I read Butters.