Here are my top four albums of 2009, with a short description of each:
I highly, highly recommend checking out Animal Collective if you haven't already. Their albums are always interesting, thought-provoking, and innovative.
Also, here is my list of the top 10 albums of the decade, based on both cultural influence and musical innovation:
(Disclaimer: This list is heavily skewed toward the indie / alternative genre, so my apologies to anyone who may be offended that some other influential albums were not listed here. I challenge you to come up with your own list and post it below.)