I used to look at what BruceH was recommending
As for jazz, the threads on the board such as 1 artist/1 record, List your favorite albums from xxx are helpful for a start, but elaborate comments in the Artist Corner or in threads such as What are you listening to (original thread and current) /What vinyl... are very informative.
As for non jazz, I much prefer RYM than Discogs (the rating system and the comments on Discogs are pretty much junk, even though I found some helpful World music lists there).
As for classical music, I tend to read talkclassical.
As for movies, IMDB offers a lot of connaisseur lists, but I still miss the original Movie thread from the BigO board, a goldmine of information for a newcomer.
Overall, lists can be wonderful to discover new artists, but I find proactive searches/reads more rewarding. And recently, I tend to focus more on listening to my current jazz collection than systematically broadening my horizons, so much records I love and own that I spin so little. But that's another issue I guess