GENIUS

I freaking LOVE Genius in iTunes!
You select a song, click the Genius button and it creates a playlist with related/similar songs! It doesn't give you random songs it actually works.
I selected Bittersweet by Apocalyptica and clicked the GENIUS button and this is the playlist it made me:

Bitter Sweet - HIM & The Rasmus & Apocalyptica
Helden - Apocalyptica Feat. Till Lindemann
And Love Said No - HIM
Lovesongs (They Kill Me) - Cinema Bizarre
Perfect Skin - The 69 Eyes
Twenty Years - Placebo
Durch Den Monsum - Tokio Hotel
Guardian Angel - Lovex
Temptation - Cradle Of Filth
Guilty - The Rasmus
The Only One - Evanescence
Our Truth - Lacuna Coil
In Joy And Sorrow HIM
Can't Catch Tomorrow (Good Shoes Won't Save You This Time) - Lost Prophets
Burn - Apocalyptica
Spring Nicht - Tokio Hotel
First Day Of My Life - The Rasmus
Wrap Your Troubles in Dreams - The 69 Eyes
The Bitter End - Placebo
Muscle Museum (Different Take) - Muse
Escape To The Stars - Cinema Bizarre
Crazy Angel - Kill Hannah
Misunderstood - Robbie Williams
Thoughtless [Live] - Evanescence
Sail Away - The Rasmus

Like seriously how awesome is that. I love most those songs. I don't know how Genius works... but I'm just going to say it's MAGIC