I wouldn't mind seeing Robin Williams as Hugo Strange. Yes, his track record has been mostly bad for the past few years, but he has given some great performances too, both comedic and dramatic. I really enjoyed his dramatic work in "One Hour Photo"
and he was quite good in "Mrs. Doubtfire"
and "Nine Months"
...definitely one of the few highlights of some otherwise mediocre films. If Nolan casts him, it would feel like one of those Tarantino situations where the director takes a once highly revered actor who has been floundering lately and restores him to former glory.
Anyone unfamiliar with the character of Hugo Strange should check out the "Batman:The Animated Series"
episode "The Strange Secret of Bruce Wayne"
. It's rather silly and Hugo is a bit of a fool in it, but it's also entertaining and shows what a fun villain Hugo can be to have around. And while you're at it, check out "Bane"
from the same series. A legitimately excellent episode and for the moment the best depiction of the character that's been done outside of the comics...of course that may change after the release of Nolan's sequel (hopefully?).