Q. Do I need Internet Explorer in order to use SharePoint 2010?
A. SharePoint 2010 is generally browser independent. Several functions work better under IE, such as, uploading files, for example. When using Firefox, you can only upload one file at a time. Multiple Files selection under the Upload Document is grayed out. Importing spreadsheets as lists is another wrinkle. Here you can get an ActiveX error. I haven’t tested all the browsers, but when doing anything other than consuming SharePoint content, I choose IE.