There is no problem dual booting with Vista and any other OS
Are you sure about that? I've heard about problems when installing one OS before the other. Apparently Vista doesn't like it when XP is already installed, when detected it will automatically try to replace it.
It might have been fixed a long time ago though, as nowadays you can even boot from an USB stick.
I know that this is something that some people disagree with, but I would get I bigger power supply. It will do you good if you upgrade some parts later that require more. 450 is kind of borderline these days.
I totally agree. In fact, I've got my fair share of doubts whether the PC will run with only 450W. 3D cards and processors do become more and more power efficient, but the overall trend is still an increase in power consumption.
Cheers
