Just saw this at John C. Wright’s blog:

Rules—
01. Anyone who looks at this entry has to post this meme and their current wallpaper at their LiveJournal.
02. Explain in five sentences why you’re using that wallpaper!
03. Don’t change your wallpaper before doing this! The point is to see what you had on!

I’m not LiveJournal, but what the heck. Here’s the image I’m currently using for wallpaper:

This is, of course, a picture of Thomas Aquinas. You can tell it’s Thomas because he’s wearing a Dominican habit and has that weird sunburst on his chest. As a doctor of the Church, he’s holding the Church in one hand and the scriptures in the other. And he’s on my desktop because I’m extremely fond of him, and because I like this particular image of him.