I have to disagree. While Star Wars a new Hope was awesome, The Empire Strikes back was better in a lot of ways.
As a film, V is probably better than IV, but without IV, V wouldn't have happened. And whilst IV stands up well on its own, I don't think V does without IV and VI. So whilst V is probably the best, I personally can't rate it above IV.
As for VII v III.5 - I've seen both now several times (although nowhere near as many as IV-VI) and find it difficult to pick a favourite. I like the continuity of VII and the soundtrack, but the story of III.5 is better and the last 30 minutes are epic. Maybe if John Williams had scored III.5 it would be better, but I still struggle a little with it because he didn't.
Roll on December for VIII. If it's better than VII and III.5 I'll be happy