Product Recommendations

Blogger Chris Bertram suggests the use of Google Sets for product recommendations. Enter movie or book titles, names of artists or games, or whatever else is of interest and get recommendations for what else you (or your gift recipients) may enjoy.
Here are some services specializing in recommendations:

Music
Last.fm
Pandora
Gnoosic
Music Mobs

Movies
MovieLens
Yahoo! Movie Recommendations
Gnovies

Books
What Should I Read Next?
Gnooks

Google Sets

Die Dulci Fruere