I checked out a great new website last night. Well new to me at least called Musicovery.com
The premise is that you select the kind of mood you are in from Calm to Energetic and Positive to Dark and then it selects a virtual web of songs to play to compliment your mood. You can register for free and select your favourites or remove songs from the list. You can choose specific decades or genres and then watch a colourful web of hits unfold. You don't have to register to just listen but you will have to register to save your playlist. It's well worth a 5 minute glance but may take a while to load up on slow machines. Here's a great song that came up in my playlist today. It's called Banquet by Bloc Party. Awesome.