I keep forgetting I'm speaking in an American accent sometimes. The dangerous thing is that you end up forgetting what your real accent is after a while! It's really strange; I've never done a job in an American accent before.
I have spent too long training myself to speak with an American accent, it's ingrained. I spend 16 hours a day on set speaking with an American accent. Now, when I try to speak with an Aussie accent, I just sound like a caricature of myself.
I do one accent - my own. I can make it louder or quieter. That is the sum total of my vocal range. I thought I could do an American accent until I tried it in front of an American - the expression of horror is still burnt onto my retinas.
For me, my taste isn't limited to magical films. Whatever I read and I like, I go up for, and a lot of the time it's an American accent which can be quite trying, but I'm working on it as much as I can.