Most people cant be arsed to sit in front of their computers for 3 months learning how to recompile their kernel just to install a desktop theme.
That is the thing that Ubuntu changes.
You can not say that Ubuntu is any harder to use or take months to learn (it takes months to master but minutes to learn).
It more or less installs itself, if you want to add a component that is not included in the basic install you click on a icon, find the component you want in a overviewable list click it and it downloads and installs itself (in this list everything that a avrage windows user would use is present).
As I said earlier you need to truly be an idiot to fail in using Ubuntu and it is much easier to use then windows.
In windows if you want to view i.e. movies using Xvid you need to go on the internet search for a site that offers you do download the codec and install it "manually".
In Ubuntu you open the components list type "codec" in the search field mark the package that contains video codecs and press "OK" and it downloads and installs itself.
In windows if you want to do some office work you need to go pay alot of money or the Office suite and install it.
In Ubuntu the equivalent is preinstalled when you install the OS (and uninstalling is just to go to the components list uncheck it and press "ok"). And there is no compability issues between MS Office and Open Office on a basic level I have worked on files and been switching them between the two (uni and home) and had no problems.
And the list of things goes on and on:
IRC client present in Ubuntu
MSN,ICQ,AIM and whatnot allready present in ubuntu.
BitTorrent allready present
DC client 3 clicks away
Firefox is the default web browser allready present
GIMP graphical editing tool simmilar to Photoshop (alltough a bit less powerful) allready present
Almost everything a normal user can think of is allready present or only a couple of clicks away in Ubuntu, and alot of the applications you have the option of several different clients (i.e, if you are not content with the default bittorrent client you can chose from a couple of other amongs them Azureus). Of course the problem is bigger if you need very specific programs (i.e. a specific CAD program etc) but most home user don't need this.
And the obvious thing is the lack of games and IMO the biggest thing holding the world back from switching to linux.
Also you don't have the windows type registry causing problems and I very rarely even use the page file in Linux it usually uses the RAM instead of doing like windows that start to page imediatly which leads to much smoother and faster usage.
