I compressed some CDs for Stella into Ogg Vorbis format.
Today she asked me how to play them, and I said that while Windows Media Player is the default media player for Windows, it doesn't support Ogg Vorbis natively, and that I use XMPlay instead.
However, it seems that XMPlay stores the last playlist used globally—so if she plays a directory for one CD, it'll wreck the playlist I use, which is currently not stored since I rely on XMPlay's keeping the last-used playlist around.
So I had a Google search for "windows media player ogg"—and was amused to find the appropriate FAQ on LiveJournal on the second page of search results :)
(Unfortunately, the link to the DirectShow filter didn't work for me since my computer can't connect to www.vorbis.com just now.)