Therion, if you don't already listen to it, which you should
I don't understand why more people don't listen to Therion, everything they've done is so unbelievably awesome. Even if they are a pretty popular metal band, there's no reason I can see that they shouldn't be way more popular
They're also on tour right now, so go get tickets you cvnts.
Fates Warning, especially the power metal albums
Suffocation, all the albums are awesome, but Human Waste stands out for me, especially the track Infecting the Crypts, which is, in my opinion, the best death metal song ever.
Cathedral can be kind of repetitive I find, but they have a lot of cool heavy sounding doom metal songs with lots of pretty melody :D
In the Woods... is good, listen to it.
Windir's pretty good too, Arntor Likferd and 1184 were good albums. To me it seems like a mix of black metal and power metal, which is kind of cheesy at first, but it'll grow on you.
Enslaved is great epic metal, Vikninglir Veldi was a spiffy album. But I'm sure there are other people who know a lot more about epic metal then me ;(
Also, Thyrfing is a pretty good viking metal band, Urkaft and Vannisevisor are solid albums, not too extreme in any way, but interesting.