I have seen and used every version of Windows (yes I'm that old lol) and yes they all looked different. If they didn't change the look no one will buy. LOL
Remember this is still beta and many part are left out from the final version.
I'm sure we will lots more information in the coming months before the release.
As far as I have heard it may be released in 2012 but no one is saying that in concrete. Actually I don't think we need another version for desktops because I feel Win7 has been the most outstanding Windows ever developed. For now I'm sticking with 7.
Sometimes no one will buy anyway due to reviews or first impressions -- Win ME or Vista for example. I completely skipped those iterations and based on what has been published about Win 8 it looks like I will be skipping it too.
That plus I (this includes my mother's 2 computesr and 3 of mine) switched over to Win 7 (I had been on XP Pro and XP x64 Pro for quite a while) only a year ago and I am not about to shell out for another OS this soon OEM prices or not.
By the time I am looking to upgrade OS again I expect Win 9 to have been out for a while.
First version of windows I used is 3.0 (briefly then 3.1 and 3.11 for a long while). Although this was more as an alternative to the command line interface (made heavy use of the DOS shell from 2.1 all the way up to the last version of 6.xx).
I did 'play' with Windows 286 and 386 but they were not good for much of anything at the time and competing environments like GEM seemed more functional.