Want to buy a new computer, so which OS is best?

Hello,

I will be filing my taxes soon and I know I will get back at least $1200, and I want to invest in a new computer, most likely a laptop. I have heard that Windows 8 still has a lot of fixes to resolve and wondering if they even sell new computers with Windows 7 loaded?

Do you know of any good brands and models that has pretty good amount of memory and disc space and fast processor?

I so much miss using my camcorder because it needs firewire to connect to a computer. Is there any such things as an adapter to change it to USB?

I am in the process of backing up everything from my current laptop onto my external HD and hopefully all the files are safe and not corrupted? How can I test all files on lappy and on external HD?

Thanks!