900W is a bit much for your needs, you should at a well-built 500-600W, such as this Corsair
. Keep in mind that the PSU is the most important part of your system, IMO; if it dies, it takes other stuff with it, and cheap PSUs are likely to die.
You might also want to go for a 1TB hard drive (or a second 750GB), video+images can take up a LOT of space quickly.
Everything else looks pretty good, though I don't know much about i7 motherboards.
As for Vista or Linux, are you able to use the XP that's on your current PC? Could save you a bit of money there.
I would say, go with whichever runs the programs you use best. For example, are there Linux versions of the programs you use? If not, do you know how well they run in Wine (Windows emulator)?