Not the kind of music I would normally like (loud-quiet-loud tends to annoy me after a while) but there's something compelling about them that I can't put my finger on. Panopticon and Oceanic are their most highly-rated. If I had to choose I'd go with Panopticon just because it seems to flow a bit better but there's hardly anything in it.

Anyone know if the other albums are any good? I didn't like the clips I've heard of the last one all that much, sounded like a budget Tool.

say Oceanic followed quickly by Panopticon. If you're coming from a 'post-rock' background that progression of records makes the most sense. If you haven't had enough Isis by then move onto 'In The Absense of Truth', it's pretty good but not a huge progression from Panopticon. You might also want to try out Pelican too, you'd proabably dig them, with them get the Australasia album. Then maybe get some Tusk and finally some Lair of the Minotaur (this has gone pretty far from post-metal now but they rule!).

I prefer Panopticon personally, but the critical vote goes to Oceanic usually.

Cult Of Luna

Though this probably makes me a bad person, they are far more listenable and accessable.

Also Envy. Because they are incredible.

Agree with most posts here, personally I slightly prefer Panopticon to Oceanic, but they are both awesome! In The Absence of Truth is definitely worth getting, if only for the track Garden of Light!