I'm very happy with firefox, and I'm seriously considering getting out of Office and also going that Linux route. The unknown is always scary though...
Yes, try it. People seem to recommend Suse or Ubuntu to get started. For example download the latest Ubuntu release (CD Image), burn the image to CD-R, restart your PC and boot from CD. You can check the OS out without having to install it on your harddisk.
http://www.ubuntu.com/products/GetUbuntu/d...direct=download
(I'm using Ubuntu but I don't know which Linux distribution is the best/hippest/coolest/...)
I still have a Windows partition because I can't get some of my old hardware devices to work under Linux (no Linux drivers and no wrappers for Windows drivers).