One, compile a short list of users who regularly comment and who maintain a high level of discourse (or whatever your discussion preference is).

Save bookmarks to their threads pages (just change the id at the end of this link)

http://news.ycombinator.com/threads?id=loumf

Which is mine, but I don't suggest you bookmark me because I barely comment.

Start from those pages, don't bother with the home page unless you are bored. Explore parents, links, etc that seem interesting.