I used to be exceedingly fond of Ubuntu and I dual-booted that and XP (for Win-only gaming, of course :evil
. Unfortunately, I fell for the idea that AMD is open-sourcing video drivers and got a new ATI-based notebook instead of the usual nVidia-based one. After multiple failed attempts to get some kind of X server working properly (aka. not at 800x600 with 256 colors) I gave up and settled for Win 7 on my main machine. As far as Windows goes, I'd say this one is shaping up nicely and it's free for the time being. I do miss my fancy key binds and devil's pie though.
Maybe next November will make me happy again.
@TheHacker
There are lots of reasons to choose some flavor of Linux/Unix over Windows and they all depend on what you need.
As far as installing programs goes, I find it's a LOT easier to do in Linux using your distro's package manager. It's also safer and less buggy because all of the packages (apps) you find in the default repositories are tested specifically for your particular version of the OS and the package manager provides a single, automated interface for getting updates to everything.
Not being able to play mp3s out of the box does NOT mean that Linux doesn't have the ability to play music. The problem is that mp3 is a proprietary format and its 'owners' want people that use the codec to pay for the privilege. MS pays and passes the cost to you, Apple pays and passes the cost to you, any mp3 player's manufacturer pays and passes the cost to you. Since Linux distros are usually free, the developers can hardly afford to pay or face legal action from the 'owners' so they do not include the codecs by default. They do provide the option of installing them separately for people living in areas where the 'owner's' claims have no legal grounds.