If you want to prepare for using Ubuntu, I’d do this by using as much open source / free software as you can get hold of that runs on Windows. In particular, try OpenOffice, though you’ll soon want to make that LibreOffice. Also, you may need a text editor that copes with unix files, as an alternative to Notepad, if you ever use that. I’ve just discovered that gedit, the very useful default text editor you get on Ubuntu, is also available on Windows. See http://projects.gnome.org/gedit/
(Of course, if you are into unix’s vi, you’ll want gVim, but that’s not for the faint hearted!)

Much of your favourite and most used software has good versions on Ubuntu. Skype’s interface is cleaner and less cluttered; there is “Chromium” (the non-badged version of Google’s Chrome) and Firefox of course. Dropbox works splendidly across platform, if you want to access the same files from Ubuntu and Windows.

The only thing I have problems on Ubuntu with (and have led me reluctantly to keep Windows capability) are
* collaborative document editing with people who insist on Word
* using some web conferencing services, though that might be soluble