How should I organize my files on a Mac?

Just made the switch and am bringing over all of my files. Don’t really know my way around the OS X interfaces – my brain is still running windows (?). Most of my files are organized in about ten main folders. Where do I put them? On the macintosh HD? on what shows up as the little house in finder (how is that different from the HD?)? I don’t want them to sit on the desktop sucking memory, but I do want access to them. Also, I’ll want to be able to access them from a virtual PC in parallels if that changes anything…