For my Last.FM update and syncing needs I’ve long been a user of iScrobbler — rather than the official client. It’s minimal, tidy and provides funcational-enough iPod updating too.
There’s a new beta of 1.5 just come out and it’s got a really neat new integration of the ‘Love’ and ‘Ban’ buttons normally associated only with Last.FM radio.

Seeing as I play my own music far more than Last.FM’s this is a mightily neat addition since the Love feature was going unused. You can also send the current track as a recommendation to someone on your friend’s list or add tags which is also quite handy.