Complied by io9.com, the list focuses mostly on science fiction, but there's also some fantasy and horror. There's a synopsis and comments on each choice in the link, if you want to read more. In no particular order:
Acacia: The War with the Mein by David Anthony Durham
Enjoyed it quite a bit. Very good epic fantasy.
Air, Or Have Not Have by Geoff Ryman
Agreed that is one of the better SF novels of the past 10 years.
The Alchemy of Stone by Ekaterina Sedia
Enjoyed this one a lot. Can agree with its placement on such a list.
The Baroque Cycle by Neal Stephenson
Only partway into it. Very good, but uncertain if it'd make such a list of my own at this point.
Confessions of Max Tivoli by Andrew Sean Greer
Haven't read.
Down And Out In the Magic Kingdom by Cory Doctorow
Good, but not worthy of a best of the past 10 years.
The Execution Channel by Ken MacLeod
Read part of it. It was OK, but didn't interest me enough to finish it last year. I think I might have traded it in recently.
Glasshouse by Charles Stross
I tend to have a sometimes violent dislike of Stross' stories. Didn't like this one at all.
Harry Potter Series by JK Rowling
Very good at times, but the best of the past 10 years? Latter volumes were relatively weak to me.
Jonathan Strange and Mr Norrell by Susanna Clarke
Agreed with its placement on such a list.
Look to Windward by Iain M. Banks
Good, but not good enough for me to consider it worthy of such a placing.
The Mount by Carol Emshwiller
Enjoyed this one quite a bit. Agreed on its placement.
Oryx and Crake by Margaret Atwood
It's better than many want to give it credit for me. So what if the author made some silly comments? The novel was a very good tale.
Pattern Recognition by William Gibson
It's OK, but nothing exciting.
Perdido Street Station by China Miéville
Agreed that it's one of the best books from 2000. I just happen to believe that the 21st century started in 2001
Rainbows End by Vernor Vinge
Good to very good story, but it wouldn't have made a similar list if I had constructed one.
Stories of Your Life And Others by Ted Chiang
YES!
Time Traveler's Wife by Audrey Niffenegger
Haven't yet read.
Tooth and Claw by Jo Walton
See above, although Walton has written some very good alt-histories lately.
World War Z by Max Brooks
Haven't read.
I've only read on a couple on the list (The Baroque Cycle, Harry Potter, Strange and Norrell) but they certainly were very good. I haven't even heard of a lot of the books on this list, actually, but they all do sound interesting.
So what do some of you more well-read folks think? Agree, disagree? What books would YOU put on your list as the best of the decade? 
Well, I already posted a list of 50 standalones from 2000-2009, but one for multi-volume works will have to wait a while.
Illusions fall like the husk of a fruit, one after another, and the fruit is experience. - Narrator, Sylvie
Je suis méchant.
Je suis méchant.
20 Best Science Fiction Books of the Decade
- 13/12/2009 10:16:32 PM
1249 Views
How can Harry Potter be there and the Dark Tower not ?
- 13/12/2009 11:53:10 PM
668 Views
I'm kinda meh on Harry Potter but at least I found it interesting enough to finish
- 14/12/2009 02:25:36 PM
619 Views
I think they put Oryx and Crake on lists like this just to spite Margaret Atwood *NM*
- 14/12/2009 12:10:35 AM
435 Views
What do you mean? *NM*
- 14/12/2009 01:52:01 PM
269 Views
She's on record as being a bit snobby about Sci-Fi and not wanting to be labelled with it *NM*
- 14/12/2009 02:23:46 PM
261 Views
I agree with her 100%. It's not Science Fiction. *NM*
- 15/12/2009 06:47:50 PM
305 Views
I don't think of books like that as Sci fi but I can see the argument that they are
- 16/12/2009 01:19:45 PM
626 Views
Read most of these
- 14/12/2009 12:43:05 AM
896 Views
I'm a little surprised The Lies of Locke Lamora isn't on there, to be honest.
- 14/12/2009 02:35:13 AM
613 Views
it's fantasy. not sf even by a stretch. *NM*
- 14/12/2009 05:52:05 AM
276 Views
Am I th eonly one who always reads Ekaterina Sedia as Ekaterina Sedai? 
*NM*
- 14/12/2009 08:52:57 PM
305 Views
*NM*
- 14/12/2009 08:52:57 PM
305 Views