i usually dont rec songs, mostly albums, but my fav meshuggah songs are I, Bleed, and Do Not Look Down. as for albums, get Contradictions Collapse, Destroy Erase Improve, Chaosphere, Catch 33, None, Nothing, obZen, and Koloss.
as for CoB, their best song is Hatebreeder, no question. i dont like their later albums as much as i do their first three (Something Wild/Hatebreeder/Follow the Reaper) but there are some good songs such as Bodom Beach Terror, If You Want Peace... Prepare For War, In Your Face, Tie My Rope, and Cry of the Nihilist.