The beautiful LastFM app.
This is a simple and elegant last.fm application for looking over your most played artists, albums and tracks in different time periods:
Last week, last 3 months, last 6 months, last year, and overall.
By default, the artist pictures/album covers are shown, but when you click on the title above the pictures, a pie chart will appear!
Besides, it will keep your statistics synced so you can open them even when you're not connected to the internet.

Screenshots: