The latest versions of Ubuntu are much better then earlier ones IMO. Far greater compatibility with more hardware, and better ease of use. I have 9.04/9.10 (can't quite remember) installed on our Family computer, and besides the lack of windows .exe compatibility (which is a good thing IMO) no body seems to really notice much thats its actually different then Windows.
Most people can achieve most everyday tasks on Ubuntu with no problems and no prior use/learning.
A problem for Ubuntu is that some people, regardless of weather Ubuntu would serve all their needs perfectly with small effort, still won't consider Ubuntu because they wont use anything that isn't widespread i.e. Windows. Windows is so widespread that any alternative will be perceived as seriously crippled to a lot of computer users. Actually, this is where marketing can be very important. Subtle marketing such as Apples product placement in films.
Now, with the fact that more people have tried Ubuntu, know that it is actually credible, the numbers of people who dont want to use ubuntu (when its convenient) is shrinking (slowly).