One thing nice about OSX is that you get to have your desktop picture change randomly every so often (you pick the frequency from a pull-down -- I think mine is set to every hour or two). So I have saved a few pictures from APOD to a directory, and pointed my desktop changer at that directory and now I've got a nice pretty starry sky to look at any time of day. :)
APOD has featured quite a few wonderful shots. Sometimes educational, sometimes just darn pretty. If it's not on your reading list yet, you may want to look into that. :)
