I'm gonig to have to say Enslaved is a big one that comes to mind. They're early stuff was amazing, but I think their stuff from Monumension up to Vertebrae are better for getting started. Below the Lights, Ruun, and Isa in particular probably give the best of all eras, but Monumension has some great stuff to pull as well when they were at their most psychedelic stage.

Mastodon I would say Crackk the Skyy might be a good place to start because it was the peak of their old sound and just began to slant into the Hunter which lead to their newer sound.

boris is one hands down that the first album will either be a make or break off the bat. It took me a while before I enjoyed it which if why I'm saying new listeners would be better off starting with Smile, Pink, or maybe even Amplifier Worship would be a better way to get a taste of all the areas of sound they go into to.

Dimmu Borgir I would say not to start with For all Tid because it's one of their best albums and you're only going to be disappointed if you let that set the sound you were looking for when you go onwards (not that the rest of the albums were bad at all, but they really changed) In the same regard I sort of need to say Behemoth, the first album by Behemoth was amazing, but you will be disappointed if you expect anything past grom to sound like it really (not that the rest was bad at all, just different).

My last bit is Bathory, Bathory had some amazing influential material starting out, but it's not a taste that will grab everyone's attention and might turn some people away at first who woul really enjoy the later work. Blood Fire Death is probably the best place to start with Bathory to get the tail end of black metal Bathory and the era wave of 'Viking' metal Bathory.

I recently got into Bathory and it was through Blood Fire Death. No other album comes close for me (yet).

In fact, I picked up BFD on vinyl today. The artwork is truly gorgeous in 12" form.

For me it was the video to One Rode to Asa Bay, but Blood Fire Death was the first full length album I listened to by them as well as the first one I bought (It was a really stingy feeling black-tray jewel case with a card insert rather than booklet from Kraze or Black Mark productions, but still) From there I ended up jumping straight to the Nordlands and back to Twilight of the Gods with a little from everything else along the way.

Gojira - that debut is so boring...Septic Flesh too...

Sum 41... seriously, have you heard the Chuck album? Great thrash album.

When it comes to Enslaved, I'd say it depends on what you are looking for. If you are looking for epic and winding black metal, starting with the debut wouldn't be the worst idea in the world. However, in my opinion, if you like more modern stuff, Isa and Ruun would be my pick for where to start. Isa is what got me more interested in modern extreme metal, instead of just listening to grimey, under produced old school stuff.

^In the spirit of the Sum 41 post, I'll say Propagandhi. Their pop punk stuff is really great too, surprisingly technical, and catchy as hell, but they really got great with the release of Today's Empires, Tomorrow's Ashes.

And the next two are even better. Not enamored with the new Propagandhi, however.

If we're talking punk, obvious answers are Bad Religion and NOFX.

Another non-punk band that fits this category - Clutch.

I guess I was just bias towards the early stuff because I know when I first got into Enslaved, I was extremely picky about my black metal, Satanic Warmaster and Windir were only raw stuff I really liked back then because it was melodic, Hordanes land through Eld wasn't stuff that appealed to me the same way I didn't get into early Darkthrone or early Burzum back then while Below the Lights was a little more listenable for someone who wasn't seasoned for black metal yet. I like all their early stuff now though. If you are already into other black metal that is less melodic then early Enslaved like Frost and Blodhemn might be a good pick.