I'm not gonna go back to 1990, too hard and not that useful, but I will take this opportunity to call attention to something kinda interesting about my personal lists going back to when I got into metal. For your consideration, my #1s as of the end of the relevant years:
2003 - Iron Maiden - Dance of Death
2004 - Iced Earth - The Glorious Burden
2005 - Opeth - Ghost Reveries
2006 - Mastodon - Blood Mountain
2007 - Porcupine Tree - Fear of a Blank Planet
2008 - Fleet Foxes - Fleet Foxes
2009 - Cobalt - Gin
2010 - Ludicra - The Tenant
Alright, so there's patterns here, obviously, and they totally mirror where I was at as a consumer of music at the time. In 2003 and 2004, I was getting my footing as a metalhead and that meant starting with easily palatable, traditional genres - Maiden and Iced Earth, bingo. 2005 and 2006 I started branching into both more stuff with harsher vocals and more progressive stuff - Opeth and Mastodon, bingo. 2007 I was obsessed with prog rock, buying up all the old 70s prog I could find and frequenting progarchives.com - Porcupine Tree, bingo. 2008, I was starting to get influenced more and more by my indie-loving friends and every indie band I like now I got into that year, I was even reading Pitchfork at the time - Fleet Foxes, bingo. The past two years I've been getting ridiculously into black metal and am sure it's my favorite genre and the one with the most creative room - Cobalt and Ludicra, bingo.
I don't make these lists with an agenda, but it sure fucking looks like it.
PS - For the record, I still like all of those albums quite a bit, but not all of them would still win their year. I definitely don't feel like reevaluating though. Let's keep 'em in a time capsule.