I come here to HN.

For certain niche subjects, Reddit comments have some good links (specific sub-reddits for a tech framework of interest, military subs with a more mature crowd like r/warcollege, etc...).

I guess I'm not at a point in my life where I'm doing a lot of discovery of "new" stuff, where I need constant exposure to new cutting edge tech or philosophical writers, or whatever, so HN mostly satisfies my needs.