Well, for gaming I use headphones... Zalman Theater 6's. And I can only turn the volume up to about 46%... any higher and I need to rip them off my head cause it's too loud.
oh yeah... x-fi sound card.
With my other PC also x-fi sound card and i've got my z-5500's hooked up. I've turned the volume up to around 89% with everything else maxed out... and the walls in my apartment start to crumble... and the neighbors start having a fit.