You definitely shouldn't have that much stuff running in the background. I have 24 processes running and that is a lot IMHO. It is pretty lean, but there are a few things that I like to have running.
First thing that I am wondering is how many of those may be worms or backdoors. You would be surprised. There are a few nasty ones like Teeskids, Welchia, etc that install on any PC with a physical network connection. Personally what I do if I see seomthign suspect is just do a search on the internet to see what it is and what it does. That is how I found out about Teeskids. Fresh install, hadn't even loaded any drivers and it was installed.
Here is a good link for services and descriptions:
http://www.blackviper.com/WinXP/servicecfg.htm