BleepingComputer.com: Want to upgrade Vista to Windows 7, but not sure which to buy?

Hope this is ok to post here since it's the Windows Vista section.

I have a new computer that I bought in 2009 and never set up, still boxed up - long story. Ready to use it but now that Windows 7 is out I'd rather use that than Vista. And I doubt Dell would offer me a free upgrade or discount.

Browsing Best Buy but there are so many Windows 7 options that I'm a little confused and not sure which is right for my computer - I want to upgrade Vista to a basic Windows 7, nothing fancy or special.

http://www.bestbuy.com/site/Operating-Systems/Microsoft-Windows/abcat0508002.c?id=abcat0508002

My computer is a Dell desktop with Vista, whatever the standard basic version was at the time, I don't know about the 32-bit or 64-bit info, I had ordered whatever ever was basic and less expensive so let's assume it's 32-bit. I primarily use my computer for the internet, I don't game, don't download movies or massive amounts of music, don't watch movies or tv shows on my computer, just basic internet surfing.

Thanks for any info!

http://windows.microsoft.com/en-US/windows7/products/compare