We haven't done much with the other features last.fm offers — I'd downloaded the last.fm player a while ago, but it didn't seem to work and I didn't feel like the hassle of getting it working.
But now they've updated the player software and it seems to work, so we're just beginning to explore it a bit. At the moment I'm listening to the custom station it created from the list of musicians I entered: Bonobo, Les Nubians, Linda Lyndell, Martina Topley-Bird, Morley, Norah Jones, Syl Johnson, The Meters.
Preliminary verdict - love it. Who needs FM radio?