Ubuntu is an excellent program for a novice who likes fiddling with computers or just likes the idea of "open source" free software. Ubuntu is one of the more "user freindly" Linux operating systems (I even have it installed on my daughters computer)
Open Source software is free, there are many programs that do exactly what many other non-free software programs do. If that doesn't work for you, you can use the "wine" program to run windows based programs using Linux.
Many internet browsers exist that are available for use with Linux besides firefox, but does firefox comes with the Ubuntu package, but nothing is preventing you from downloading another.
There is a learning curve to using Linux, although there is a pacakge manger (download assistant) that makes alot of things very easy, there are times when you will have to use the command line (I found this mainly during initially setting up the OS, like for my daughter I installed dansguardian ((internet filter)) & beryl ((for eye candy)) using the terminal) both were fairly easy to do using online walkthroughs.
the biggest learning curve is just realizing this is not windows, every problem I've ever had, I found within a few minutes using Google or the Ubuntu Forums.
The greatest things about Ubuntu is it's ease of use, relatively short learning curve & it's large support community, these things make the transition to Ubuntu fairly easy.
Free free to conact me with any questions you may have about switching to, or installing Ubuntu.