I'm with Erik, 2008 hasn't had too many mind blowing moments for me and there have been a handful of "that's it" reactions when albums came out. My favorites thus far:

1.The Notwist: The Devil, You + Me
2.Girl Talk: Feed The Animals
3.Hot Chip: Made In The Dark
4.My Morning Jacket: Evil Urges
5.Vampire Weekend: Vampire Weekend

Although technically In Rainbows was released in January, so I guess that makes 2008 a whole lot better if you want to split hairs.