Emperors "masterpiece" is something that isn't entirely agreed upon. Their most "true" (excluding the hideous demo) record is probably the "Wrath of the Tyrant" split album with Enslaved, which is the only Emperor some of my "true" friends can listen to. This of course means nothing, but fortunately it's pretty good, although I prefer the Enslaved part. I don't believe anyone would deny that their second studio album, "In the Nightside Eclipse" is the greatest classic of Norwegian black metal ever. It includes such classics as "Inno a Satana" and "I am the Black Wizards", and is my favourite Emperor/Black metal album. "Anthems to the Welkin at Dusk" is also great, and somewhat more accesible, but didn't inspire me as greately as "In the Nightside...". Both are superb, and I would reccomend getting both.
IX Equilibrium is not really worth mentioning, I found the album quite average compared to their previous masterpieces.
Yeah, Projector's great, and Haven's even better.