You can use the SC in the command line to enable the service when you need it and disable it when you don't using a BAT file. (sc config servicenamehere start= disable)
Well, clearly this will never be the year of the windows desktop until users never have to interact with the commandline for anything. They should scrap entirely in fact because users should never need it.
Right click on 'My Computer' -> Click 'Manage' -> Expand the tree and find 'Services' -> right click the service you would like to disable -> click 'Properties' -> disable it -> click ok.. Yes, because that's so much easier than running that simple command.