Great summary Gareth, thanx for taking the time to post it
Not much else i'd like to add. One important thing I should say is that the way Linux apps are installed forces many users from using Linux.
For XP, its easy. You just double click, follow the wizard and its done. With Linux, if your software supports RPM packages, you are in luck. However, a lot aren't. Because there are so many flavours of Linux, you normally have to compile the source. You are given step by step instructions, but it doesn't always go smoothly. A lot of times you need to download extra libraries etc to get it to compile. Installing programs therefore is a normally an arduous process with lots of googling needed.