iScrobbler... An alternative to the bloat-ware that is the "official" last.fm client.

• Full Radio support.
• Integrated iPod support.
• Local Scrobble lists and profile charts.
• Scriptable
• Minimal or full detail interface - your choice.
• Native OS X app - no intermediate code to slow things down.
• Stable and lightweight.
• Lots of other goodies.