Hmmmm..... Many of my favorites this year have been outside the metal genre, but their have been a few.
Katatonia Dead End Kings - A great follow-up to Night is the New Day, while more somber/melancholy as a whole, it's a definite top album for me this year.
Paradise Lost Tragic Idol - Paradise Lost has been on a roll since re-embracing their metal side with 2007's In Requiem and then following it up with, one of my albums of the year for 2009, Faith Divides Us - Death Unites Us. Perhaps there's a trend forming with this somewhat gothic/doom trend in my list - probably not as that's it for the quasi-doom stuff.
Kamelot Silverthorn - After Roy Khan's departure following the last two releases that I felt incapable of living up to their epic The Black Halo, I had sort of written off Kamelot. Then came the touring with Fabio Leone of Rhapsody fame and while a good singer in his own right, I really did not want him as the permanent replacement. Fortunately they found the perfect replacement when Tommy Karevic of Seventh Wonder joined the band as Khan's replacement. Karevic's uncanny ability to sound almost exactly like Khan at times will help with performing older material on tour, but he has also shown that he might be considered a better singer overall with greater range, differing styles that bring his own voice to Silverthorn.
Silverthorn really surprised me as I thought Kamelot was on the back side of their careers after two lack luster relases (when compared to The Black Halo at least). It's gotten a ton of listens over the past month or so since it's release and worked it's way to the top of my power metal category it seems.
For metal I'm sure there are others, but I'll have to think a bit more about it.
Non-Metal stuff that's been finding itself in my regular playlists this year:
Joe Bonamassa Driving Towards the Daylight - The busiest man in music was involved in at least 6 releases I'm aware of this year - a album he did with LA based singer Beth Hart Dont' Explain (great album if you like that type of music - blues/jazz classics), his Beacon Theatre: Live from New York release on DVD and CD, his solo disk, the aforementioned Driving Towards the Daylight, another 2012 favorite is his "super group" effort with Hughes, Bonham, Sherinian, and the fifth member of sorts, producer Kevin Shirley titled Afterglow, plus he played on Jon Lord's final disc, the rerecording of his Concerto for Group and Orchestra, and at least two tribute albums - the Deep Purple Re-Machined album and the Tommy Bolin disc Great Gypsy Soul. This album represented a little less of his rock side and more of his traditional electric blues side and Kevin Shirley did a great job on the production.
Black Country Communion Afterglow - The bands third studio disc proved to be a bit of a tipping point between Joe Bonamassa and Glenn Hughes in regards to their quite public argument over the future of BCC. Glenn Hughes see's the magic BCC has been creating as a re-emergence of classic rock and quite possibly of his recognition as the "Voice of Rock" while Joe Bonamassa see's BCC as the side project he does every now and then but it is in no way his primary band. His solo career pays the bills and he is a man of habit - he records a solo disc every year and tours in support of them after their release. a point he made clear upon joining BCC.
Despite all this turmoil, Afterglow turned out excellent. For those looking for that classic rock sound with a modern production, Kevin Shirley and the band once again delivered.
Coheed and Cambria The Afterman: Ascension - C&C went through some lineup changes since the release of their previous album The Black Rainbow with Chris Pennie leaving, being replaced by original drummer Josh Eppard (now sober and clean after problems with addiction) and bassist Mic Todd's drug related robbery charges resulting in his removal from the band and new bassist Zach Cooper joining the band for the new disc.
I got into C&C like many with the Good Apollo IV volume I release and subsequently getting into their back catalog - they quickly became one of my non-metal favorites. Unfortunately I thought they lost something on both GAII No World for Tomorrow (still enjoyed it, but less so than GAI) and The Black Rainbow (I like it more now than when it was released, but I still have issues with it.
The Afterman: Ascension is disc one of a double disc release - the second part titled The Afterman: Descension comes out February 5th of next year. On Ascension they offer a good mix of styles from old C&C to newer stuff they worked in on NWFT and TBR and came out with a really great disc.
While they may now be everyone here's cup of tea, they work for me in an extremely original way that much modern music lacks.
As always, individual mileage may vary.