Regarding At the Gates: I grew up listening to Slaughter of the Soul and that album basically taught me how to play and write metal. I don't listen to it much anymore for the same reason listed above: I've heard it a Brazilian times. However, I also like the rest of their stuff, but none of it had nearly as much of an impact on me as SOTS did.
Regarding Hypocrisy: These guys introduced me to death metal with Abducted, which is still one of my favorites. I've always been most partial to their mid-era material: The Fourth Dimension, the aforementioned Abducted, The Final Chapter, and the self-titled album. Osculum Obscenum and Penetralia are early favorites as well, but not a patch on the others I listed.
Regarding Entombed: I have dedicated my life's work to recapturing the guitar tone on Left Hand Path. It's funny, but the three bands I've seen people talking about here most recently all recorded the albums (SOTS, Abducted, Left Hand Path) that have the absolute best guitar tones I've ever heard. Regardless, that Entombed record is timeless, a drunken, punk-infused death metal battering ram of an album that no recent release I've heard has been able to top. It may not be the fastest or the most brutal, but the songcraft is top-notch.