Being able to indicate we aren't available for chat would be awesome. I always feel bad when I miss an IM if I'm away or mindlessly chipping away at rocks while on a call or something - especially when the IM came from one of my new low level friends looking for a touch of help/advice (which, as a greeter, I have a few of and I'd hate for them to think I'm ignoring them). Not to mention the times when I just don't want to be social and, instead, want to hide in my house petting my piggies and tending my herbs or get all nostalgic on a trip through the ancestral lands.