Ummm... how will Elemental support 64-bit XP? Impulse doesn't support 64-bit XP.
obviously they will have to fix that. (though, 64.bit XP is pretty broken in my experiance. I don't think anything supports it really. I mean, does 64-bit photoshop even support it?)
I'm running impulse on 64-bit windows 7 right now and it works just fine. I mean impulse is running as a 32-bit program, but that doesn't mean it can't install a 64-bit game.
They also said that both 32-bit version and 64-bit version will be on 1 DVD, so if push really came to shove and they couldn't get out a compatible impulse somehow, you could just get the disc. you can buy the disc off impulse. I want whatever special goodies that comes with the collectors box anyway, so its no harm to me.