Duh I've seen an Xbox with my own freakin' eyes.....
And I'm pretty sure, you can't save a file then download it onto your Xbox 360 then watch it, or play it.
You can do the same thing with a transfer cable from your PC to xbox, or a USB flash drive.
So like I said, minus internet browsing (because you'd most likely be able to do this as well once it was implemented probably).
It's a gaming console, I see no need for what you just said as OP has a computer to do this