Even if you didn't notice album art, you won't have missed the notification support in Rhythmbox. Unless you've disabled it, a notification bubble should pop up every time a new song starts.
But what if you combined the two? Well, you'd have flashy song notifications, wouldn't you?
Even the tooltips can show album art now - perfect for those of you who've ever bought an album solely because it had a shiny, shiny cover... (it sounds alright though)
Apologies for the lateness of this post too ;)