Hi and Lois is easily the most interesting legacy strip, if only for its wide variety of tones. It usually settles for simple gags, but occasionally forays into more controversial territory (I can't find it now, but it has explicitly acknowledged global warming in a nonjokey way before) and at times into outright misery, as is the case today.
Seriously, there's no humor content here. This is just a comic about an alcoholic, his unhappy wife and their collapsing marriage. Of course, the timeless state of the comic means that the marriage will never actually collapse, but remain in a perpetually collapsing state. But that only makes it all the more depressing.