I’m using the iScrobbler client on OS X rather than the default last.fm one as it purports to include the Last Played playlist from iTunes in its scrobblings. This is useful seen as all my music is either on the iMac, or my iPod. Hence you won’t see any updates whilst at work for example until i dock the iPod.
The range of music won’t exactly be representative of my tastes either as I’m currently in the process of re-ripping my quite substantial music collection to a lossless format (FLAC to be precise.) I think I’ll have to go through and prioritise the order they are done in. Already I am pleasantly surprised by the music Andy and Roo seem to listen to. Especially to find out that Roo is a fellow Reindeer Section fan.
Edited to add: Just discovered that iScrobbler has an option to scrobble any shared music I play. That means anything I play from my Linksys NSLU2 NAS device running mt-daapd gets logged as well. This means I can withdraw my comment about not having my full music library at my disposal!