That's pretty much what I had in mind when I changed the text for "mood." I figured it would come up as "mood" (or whatever people have theirs set to) on Friends pages, and I decided that actually worked, for just the reason you say. It's often enough that I choose which book to read next based on mood. "Hmm, I'm just not in the mood for an Ellis Peters right now. I feel more like a Lawrence Block." :)

Plus, I always used the "music" feature occasionally, and the "location" feature makes me laugh, so "mood" was what was left to designate for current reading, and I've never used moods on my posts.