QuickTime 7.5.5 was the prep, Front Row 2.1.6 the side dish, but now the main event, iTunes 8 itself, is available from Apple for your downloading pleasure!
iTunes 8 includes Genius, which makes playlists from songs in your library that go great together. Genius also includes Genius sidebar, which recommends music from the iTunes Store that you don't already have.
With iTunes 8, browse your artists and albums visually with the new Grid view; download your favorite TV shows in HD quality from the iTunes Store; sync your media with iPod nano (4th generation), iPod classic (120GB), and iPod touch (2nd generation); and enjoy a stunning new music visualizer.
iTunes 8 and iTunes U are now accessible with VoiceOver on your Mac.
Updated: Now available via Software Update, or you can grab it from Apple.com right now!