1. The National - High Violet, by far the best album of the year!
2. The Beach House - Teen Dreams
3. MGMT - Congratulations
4. Arcade Fire - The Suburbs
5. John Grant - The Queen of Denmark
I just bought Sufjan Stevens - The Age of Adz and Walkmen - Lisbon, both of which are possible contenders for spots 2.-5. based on first impressions. I was also pleasantly surprised by the new Belle and Sebastian album.
All in all, I think 2010 was a really good year in music.