Sticking favorite 5 only, I'd probably go:
1. Winter Soldier
2. Thor
3. First Avenger
4. Dark World
5. Guardians of the Galaxy
Won't see Ultron until Saturday, though (and then again on Sunday).
Of the Marvel trio last year, Winter Soldier was the best.
As for The First Avenger, I think it's very close to perfect. The absolute best thing, Hayley Atwell aside, is how firmly Steve Rogers is established; and that sets the tone not only for the rest of The First Avenger but also for Winter Soldier and Avengers. For my money, however, what kept it from being absolutely perfect are two clumsy montages: first to divide Cap's early action from his climactic battle with the Red Skull; and second, not so much a montage, but the connecting scene that takes us to current day. Somewhere in the first one, Bucky gets unceremoniously lost, and the second was just awkward. To be fair, I haven't re-watched it since its theatrical release, but I recall those being my impressions at the time.
And as for Hulk, while I thought neither Hulk nor Incredible Hulk were very good, I like Bana Banner better than either of the subsequent Banners. And, nobody, nobody is Hulk better than Ang Lee himself. I say that half-jokingly, because of how Ang Lee, explaining why he personally acted as Hulk for motion capture, proclaimed something akin to,"Nobody knows how Hulk moves but me." However, watching that Hulk in action is really the Hulk that I enjoy best, so, at least in my case, Ang Lee was right.