Linux is an extremely good operating system, though more for the advanced user. Any programs you can get on Windows, Linux can either emulate this (run a windows program on linux) or, most likely have its own version.
Linux overall is one of the most stable operating systems created, which is why it is mainly used for server purposes (as they are rarely turned off). If you are not already familiar with Linux though, I do not suggest emigrating from windows XP to linux.
Try using a virtual machine to test stuff first such as http://www.vmware.com/
< vmware. This program runs any OS and runs the software while you use your windows xp as you would normally. Though you do allocate memory and HDD space to it.
Overall, I'd give linux a 7/10. The reason for the 7 is because it does virtually everything windows does, but its missing the three as new games and software is not designed for linux, though there is always an alternative, but most of us find what we like and just stick with it.
For example, photoshop is one of the most common image editing and creating programs, but there is an alternative commonly found on linux distros: GIMP, I find it very good but I think I will always stick to Photoshop.
Also, if you are insterested in emulating windows software use
For gaming, which I have used before (and amazingly found it better quality and performance, which is hard to believe!): Cedega: http://www.transgaming.com/
Hope this is helpful.