My work Dell PC's keyboard and touch pad get shiny because of heavy use (usually without the external keyboard and mouse). Typically, PC's touch pad is black. So, when it shines, it shines more noticeably than Apple's white touch pad.
So far, I have been able to keep all of my Mac's keyboard and touchpads in the mint condition because I use external keyboards/mouse/Wacom tablet and keyboards are also covered by iSkin. I also wash my hands before I use my Mac.