Bare minimums? Remove the autoupdates, the adobe stuff, the antivirus/spyware stuff, the symantec stuff, messenger, java, viewpoint, quicktime, what the heck is that HP kbd thing?, and probably the AUTOTKIT in the HP folder.
However, it would be better to disable from within each apps settings, or even better uninstall them all the way.
And are you comparing mame games with PC games? You're comparing apples to elephants.