I got Home Premium (upgrade). I got it because the Business or Ultimate versions were a bit overkill for me as far as features go. Especially for the price they were asking.
Oh, and at least in the case of the upgrade versions (dunno about full retail or OEM versions); the disk for the x64 version isn't supplied with it - you just get the 32bit version on DVD-ROM. You'll have to order the x64 disk on-line from Microsoft for an extra €10,-. You can also order the 32bit version on CD-ROMs there too. The 64bit version IS supplied with the Ultimate upgrade though.
I don't think you understood what I meant with the My Computer address bar buttons.. I meant this:
http://stuff.tombs-stuff.org/mycomputer_vista.jpgThe folders shown in the address bar are actually buttons to click.
I knew the directory tree was shown when you open Explorer with Win+E. BTW - you can also click your Start button with the right mouse-button and select "Explore" for the same effect.