I agree about Gorguts and Immolation. Most veteran death metal bands have either disbanded after one or two albums, or started releasing weak albums, but not them (though Gorguts may never release another album, they were all good).
I never claimed to be an elitist, so I must say, that Nile has a good recording record. The first two were good (though bad production made Catacombs not as good as it could have been) to great. They are one of the only bands I can think of that actually gets better with each album. I like Incantation's latest, but they have had some weak albums in between, such as Blasphemy. Dismember have never released a really bad album, but they have released a few that are just "ok," so they do not qualify. But at least they always stuck to their death metal roots, unlike Entombed.