Windows Vista wasn't that bad really, it had some problems which Microsoft could of indeed spotted before releasing and what not and yes testing more would of been ideal. Even MS themselves have commented on how Vista was some what of a fail (not sure if they exactly said that, but they acknowledged what certain people were saying) It got better with the service packs didn't it?
Now they made Windows 7, an operating system that I believe is a very good OS to use on a daily basis. Now Windows 7 has sold millions and is like the best selling operating system to this date.
Windows 8 will be important for Microsoft to get right because I'm sure they do not want another Vista in that sense and would love another success like Windows 7.
Windows XP > Blah, it's like 10 years old. Time to move on!
---------- Post added 13-04-2011 at 10:54 PM ----------
All I can say to that is, wait and see.