I don't agree with all their choices (I think Bill Georgaris is a fool--in the Biblical sense--for recommending Fahrenheit 9/11) but I think They Shoot Pictures, Don't They? is an excellent site nonetheless. Here, you can find many lists of great movies. It is "an excellent starting tool for aspiring movie buffs to begin (and also plan) their 'serious' film-viewing experiences". If you're looking for suggestions for your queue, they have thousands. I love lists. They have several lists of the 1000-best and 100-best type.
I also recommend Filmsite, which has lists coming out the wazoo, but beware of pop-ups.