Worst movie I have seen would have to be Cowboys and Aliens, cowboys and aliens come on! I thought I would give it a shot it wasn't the best thing ever. The graphics and stuff were pretty awesome, but something about the old West and Aliens just doesn't mix.
The best movies I ever see are anything by Hayao Miyazaki and Studio Ghibli.
The best of those, Castle in the Sky
The worst of those, Ponyo.
(I love them all though so yeah lol)