Let’s talk about support
First off, we know for a fact that Safari and Chrome support Transitions, because we’ve all been using one of them to see the cool crap people have been doing. FireFox 4 will support it and they keep adding to it all the time. IE9, as of what I have read, will not. They are still missing a lot of other things, so this is not surprising. But since it is still too early to tell, who knows what the final product will have. The main thing to know is, if you haven’t started getting your CSS3 chops down, you should start. It won’t be long before we are using it on a regular basis. Personally, I use quite a few, but transitions is one that I have stayed away from.