out of the "big four" of thrash, megadeth are probably my favorite, as they keep making stuff that's actually relevant, unlike the other 3. metallica's albums from ride the lightning to and justice for all beats megadeth for thrash, though. megadeth is more speed metal than anything. megadeth are coming out with something in 2016, but judging from the song they just released, fatal illusion, it's not going to be a huge improvement. still better than super collider, though.
i've also gotten more into progressive metal than before (used to only listen to metalcore such as it dies today (best album: sirens), darkest hour (best albums: the eternal return, deliver us), still remains (best album: ceasing to breathe) etc.), and periphery remains a top favorite, but veil of maya and born of osiris came out with some of their best albums this year (matriarch and soul sphere their 2015 albums, respectively. changing singers and signing for sumerian really revitalized the boring chugging sound that veil of maya used to have.) periphery also came out with the two juggernaut albums, which are both masterpieces in their own right.
one big progressive release that came out this year that i didn't like much was tesseract's polaris. it has a weaker sound than their previous album, altered state (which is by far one of the best progressive albums out there), and since the band doesn't do screams any more, it just sounds flaccid. people are giving it rave reviews, but it's hard to see why. less atmosphere, more mindless, directionless chords.
biggest thing to look forward to is dream theater's upcoming album, the astonishing. they haven't released anything from it yet, iirc, but it should be interesting. it's themed around some kind of magic show... dream theater always liked to sound a little dramatic.
from the alternative side, i still only really listen to trivium. though trivium's release this year, silence in the snow, is probably the worst album they've ever put out, even beating 2013's vengeance falls to how bad it was (not that vengeance falls was all that terrible, despite complaints from diehard fans.) trivium said it'd be a vocals-focused album, but even though matt's singing has improved, the instrumentals have fallen drastically, and now you could barely distinguish trivium from other cookie-cutter heavy metal bands that pop up once in a while. shogun is still their best release by a country mile, though ascendancy comes close.