Opeth
I discovered Opeth about 2 years ago and they have rapidly become one of my favorite bands. Blackwater Park rightfully gets a lot of praise as their best album, but I fell in love with Ghost Reveries. I'd easily put that into my top ten albums of all time.
Opeth is an amazing band. I discovered them several years ago, and they were one of my top favorites for a couple of years. I don't listen to them nearly as much as I used to though. Blackwater Park and Ghost Reveries are both excellent albums, but I've always been partial to My Arms, Your Hearse. I still haven't listened to their latest album.