I watched the announcement, replayed this afternoon. Capaldi has a rather lightweight voice to be playing a character everyone listens to. But he was just speaking as himself on the announcement show, not acting. We'll see.
You know, they say your favorite Doctor is the first one you watched. That may be true in my case, as Tom Baker will always be THE Doctor to me. Matt Smith is a close second, but Baker really understood the whimsy of the role, with his bug eyes and mass of curly hair and the impossibly long scarf that he never once tripped over (we'll leave the shtik to Sylvester McCoy). I liked his companions too, especially Leela, who must surely be an ancestress of Fiona in Burn Notice ("Let's kill them!"). But no matter who's playing the Doctor, this show is always fun.