Billy Crystal as Harry. I couldn't fancy him, so I didn't see how she could!
Tom Cruise as Jack Reacher - neither my DH nor I could understand that casting, both in height and looks. Mind you, I can't think of anything I do like Tom Cruise in, so I'm guessing I just don't like Tom Cruise.
Going against the grain here, I thought all the Harry Potter young actors were spot on, and I had read all the books before I watched their matching films. I think I liked the sort of "awkwardness" of the main child actors because it helped show they were different to muggles. I felt that they sort of needed that difference, and whereas in most book to film conversions I don't usually agree with the acting choices, these seemed very good to me.
Again, someone didn't like the cast of Twighlight, I thought they were just right.
Renee Z IS Bridget Jones.
Leonardo DiCaprio way too young looking for Titanic.
Daniel Craig as James Bond - no just no. I don't find him at all good looking, and he does not do suave/denonair. However, so many woman seem to swoon over him, so maybe I have a wonky taste in men!
I know this thread is miscast, but I think the choice of Eddie Redmayne in Fantastic Beasts and where to find them, was inspired - he is brilliant in it.