Kinda strange they didn't play New Millenium Cyanide Christ or Suffer in Truth, 2 of my favorites but still a great set.
To a new listener I'd recommend Chaosphere and Destroy Erase Improve. Once you've gotten into them I'd recommend Obzen, Nothing and I.
The old stuff Contradictions Collapse & None are really cool but much different their later stuff really.
I'm a huge Meshuggah fan but I still don't really get Catch 33. I'm hoping someday it clicks with me but it hasn't yet.