It kind of depends what you're after. My favorites are TNT and Millions Now Living Will Never Die. Those are much more in dub/post-rock/understated territory. 'Beacons of Ancestorship' (most recent one, I believe) has a much more propulsive and live sound (where Millions etc. and even more so TNT are very much products of the studio and production). Standards and 'It's All Around You' are somewhere in between.
Actually around the time Millions Now Living came out, the guy at the record store recommended it to me, and it starts off with the 20-minute+ 'Djed', which I now love, but it was not a song to make an immediate impression.
The first album I can honestly take or leave. It comes across now as more of a collection of riffs/ideas than as a cohesive whole.
I saw them live a couple of years ago. It was a great show, I hope to get a chance to see them again sometime.