On the music side here's stuff released in 2010 that I gave a good listen to (listing isn't based on ranking):
OK Go - Of the Blue Colour of the Sky
Ted Leo & the Pharmacists - The Brutalist Bricks
She and Him - Volume Two
The Hold Steady - Heaven Is Whenever
Eels - Tomorrow Morning
Belle & Sebastian - Write About Love - B&S fall into the same category as the Hold Steady for me, my opinion is always too deeply influenced by their previous work. In this case however, this feels like a more natural progression from their previous work and Stuart Murdoch's God Help the Girl project. This one is growing on me and is among my favorites for the year.
Jonsi - Go
Broken Social Scene - Forgiveness Rock Record
David Bazan - Curse Your Branches
Vampire Weekend - Contra
Girl Talk - All Day - Gregg Gillis does the mashup thing so well, and it's fun to listen just to play the "name that sample" game, but part of me wishes this could be something that it isn't - a Negativland-esque critique of pop culture and politics.
For a broader take on the music of 2010, check out my friend Rudy, he's got the critical ear and depth of knowledge I respect.
In terms of books my my two absolute favorites that I read this year are Seth Godin's Linchpin: Are You Indispensable?
I also read Leonard Sweet's book Nudge and Dwight Friesen's Thy Kingdom Connected as part of Ooze Viral Bloggers, reviews are here and here - each book had it's moments, but neither was extraordinary. Malcolm Gladwell's What the Dog Saw, World War Z by Max Brooks, and Under the Dome by Stephen King, were also among the 2010 reads - all 3 are good, but I felt King's could have been better. I know there are other books that should be on this list, but it's getting late and I haven't kept good track of what I've read.
I know there are other media I could add to the list: movies, blogs, magazines, but I'll give that a pass this time out.
[Just as a disclaimer, all the links (except for Girl Talk) are Amazon Associate links so I do get a small percentage if you click and buy].