If you want to know why, click here. My basic criteria was needle time: what have I been playing the most, and what will I want to play the most in the future. This helps to explain (though not expiate my guilt over) the lack of hip hop - there are a lot of years here where a rap record might land at number two or three, but it would be disingenuous of me to pick Fishscale or Madvillany over The Thermals or Arcade Fire when the iTunes play counts don't bear that result out (incidentally, this approach kept Bjork out of the top spot in '97 over OK Computer).
1981: Elvis Costello - Trust
1982: Michael Jackson - Thriller
1983: New Order - Power, Corruption & Lies
1984: The Replacements - Let It Be
1985: The Smiths - Meat is Murder
1986: Peter Gabriel - So
1987: Guns 'N Roses - Appetite for Destruction
1988: Pixies - Surfer Rosa
1989: The Cure - Disintegration
1990: Depeche Mode - Violator
1991: Nirvana - Nevermind
1992: Pavement - Slanted and Enchanted
1993: Smashing Pumpkins - Siamese Dream
1994: Weezer - Weezer ("Blue Album")
1995: Pulp - Different Class
1996: Belle and Sebastian - If You're Feeling Sinister
1997: Radiohead - OK Computer
1998: Neutral Milk Hotel - In the Aeroplane Over the Sea
1999: Magnetic Fields - 69 Love Songs
2000: Radiohead - Kid A
2001: Daft Punk - Discovery
2002: Spoon - Kill the Moonlight
2003: TV on the Radio - Young Liars EP
2004: Arcade Fire - Funeral
2005: Fiona Apple - Extraordinary Machine
2006: The Thermals - The Body, The Blood, The Machine
2007: LCD Soundsystem - Sound of Silver
2008 (so far): Erykah Badu - New Amerykah Part One (4th World War)