Apparently, there's a rumor going around that Benedict Cumberbatch (above) is going to play The Master in Doctor Who's 50th Anniversary special in 2013. I happen to think the rumor is baloney, mostly because it's way too early for anyone to know anything, and also because it comes from an "unnamed source" at the UK tabloid The Daily Express. Wishful thinking on someone's part, perhaps.
Not that it's such a bad idea. Cumberbatch is amazing as Sherlock Holmes in BBC One's Sherlock, which is also written and executive produced by Who's Steven Moffat. I think he'd be a really good Master, and I say this as someone who thought John Simm was the best Master since Roger Delgado originated the role in 1971 and hopes every day that Simm will come back. (I also think Cumberbatch would be a really good Doctor, though apparently he turned down the role.)
The 50th Anniversary isn't happening until November 2013, which is a long way off yet. There probably isn't even a script at this point, let alone any casting locked down, but if Cumberbatch should wind up playing the Master, I don't think I'd miss John Simm as much.