Just look at the front page of HN today - 3-4 stories somewhat about law (but relevant computer related law), the other 26 a hugely diverse array of links to interesting topics.
Even if the discussion can be a bit asinine at times, the value of the links alone is worth it, and there will be at least one or two interesting discussion threads per link.
Just ignore the crap.
Even though the quality of discussion on HN might ebb and flow, or there might be more negative comments than positive at times, the culture here isn't ever going to tolerate Natalie Portman, hot grits, or image macros.
What you see on both reddit and slashdot is an increasing tendency toward irony as the basic approach to any subject (4chan is the same way too). This overwhelms and actively drives away discussions that are serious and not ironic. This is why the highest quality subreddits (like askscience and askhistorians) enforce very strict rules and actively discourage humor for humor's sake. This is a big reason why stackexchange is so successful as well. And it doesn't mean humor is unwelcome at all these places, just that it needs to be part of something productive or humnorous enough to overcome the strong bias against it.