I found these lists http://www.sydlexia.com/top100nes.htm http://www.sydlexia.com/top100snes.htm and they seem to be quite complete, I'm very pleased to complete my collection with additions from there. Do you know of any similar lists for other systems?
I found this page handy for mini-reviews on games for systems that came out in the early '80s and late '70s : http://www.videogamecritic.net/ Most reviews are one paragraph long, and accompanied by a screenshot. I don't agree with a lot of them, but it's great for a quick description of a game you aren't sure about, and usually you can tell if you'll like a game he doesn't like, or you won't like a game he likes from the review. I wouldn't use it for anything after the NES or SMS, as the games are more complicated by then. He's missing a few systems, as well, like Channel F. If you're just looking for the top games, you can usually just look for games that get A and A+ rankings.
Someone on another thread recommended me this site: http://www.racketboy.com/ It's really cool, and very complete, has lists of the best games for many consoles, and by genres.