Great thread...I actually thought of making one along these lines myself. I've actually discovered a lot more music from previous years than this year, so my list would be a lot longer. I'll try to narrow it down to 5:
XTC - Skylarking
I have actually had this album for a few years, but it wasn't until a couple months ago that it completely clicked and now it's been on rotation constantly. Albums that all of the sudden reveal their brilliance are my favorite kind, and now this is easily one of my favorite albums of all time.
Broadcast - Tender Buttons
Broadcast are probably my favorite discovery of the year. They kick started a psychedelic craving like no other band has. After obsessing over their whole discography, I moved on to some great 60's psych that I never knew existed.
Entheogenic - Spontaneous Illumination
I've also had an intense obsession with Goa (psychedelic) trance this year. While there have been some greats (Hallucinogen, Astral Projection, Doof), these guys stand apart. They slow down the tempo and beef of the psychedelics to produce some truly great music. This album is so relaxing. When I'm pumped I reach for your everyday Goa...when I need to meditate I pull this one out.
Gorgoroth - Incipit Satan
I live with a giant metalhead who plays in a metal band, so eventually the stuff rubbed off on me. I listened to metal in high school, but fell out of favor with it shortly after that. It wasn't until this last year that I have rediscovered it. I love music with atmosphere, so black metal is hands down my favorite. Gorgoroth is one of the better know black metal bands, but I feel it is for good reason. This album is just great.
Bethany Curve - You Brought Us Here
My favorite shoegaze discovery of the year. So atmospheric, so many guitars, and so damn addictive. Everyone needs to listen to this album...it is just amazing.
Ok, one more...
My Little Airport - Zoo Is Sad, People Are Cruel
I had a bit of a soft spot for twee pop this year, and My Little Airport takes top honors. Twee is great no matter what country it comes from, but for some reason when Asians do it, it just fits. Their accents when they sing in English are so endearing and the songs in Chinese are so catchy and well written that you will swear you can understand what they are singing about.