As long as theres a fixed size rule(in KB) for the sigs, I think animated ones should be allowed.
It's not like the people that play FH2 don't have computers that can handle animated GIFs.
I don't like it. Some people have slow connections, maybe not in Europe, but there's still quite a few people who'll need 3-4 seconds to download 600kB. It slows them down quite a bit. I personally suggested a 200kB limit for animated signatures, however, I'm not the majority, so let them decide.