I like the idea of this list and feel I have to put my two sense in on how your predictions turned out for some of these movies (in my humble opinion of course)...(based on scale of ten)
Harry Potter - 6
Spider Man 2 - 6
Chronicles of Riddick - 6
The Day After Tomorrow - 2
Troy - 6
Shrek 2 - 7
Van Helsing - 4

All in all, pretty good instincts...except for Shrek 2, but I had my reservations about that before I saw it as well