When you are going to move from Windows to Ubuntu you should be aware about versions to move. So If you are looking to move to Ubuntu you should select LTS (Long Term Support) version. Currently latest Ubuntu LTS version is 12.04. Most of the times LTSs are more stable than other versions.
Also now Firefox is getting other side. So you should install Google-Chrome. Otherwise with Firefox you will fed-up with Ubuntu. It's better if you can use Google Docs more than Libre office. Because Personally I don't like to use LibreOffice.