As a disclaimer, my father used to watch old campy 50's SF with me. Further, I have always loved airships. As kieri, wonderwombat and chaosrunner can attest, if you give me airships or alternate technology forms (steampunk especially) I will be a happy girl. I do not think I have yet run a tabletop fantasy campaign where I did /not/ somehow work airships into it. So I've always loved old pulp 'air hero' stories; I think Crimson Skies is hands-down the best game for the X-Box, for instance. :)
So a movie which was in the style of old 50's science fiction, with a 'pulp air hero' feel, involving zeppelins and giant robots... well, let's just say it already has a few points in its favor for me.
That said, Sky Captain was precisely what I expected.
The plot is somewhat corny, in that contrived way old pulp SF and air hero stories were, but I almost would have been disappointed if they'd tried to make it into a deep epic; pulp tales deserve pulp plots, if that makes sense. I really liked the visual feel. The acting was totally over the top, but again, that felt right for the setting and story. I really enjoyed it, and since I know my father's taste in those areas, I plan to go see it again with him sometime soon; I know he'll really appreciate it.
However, I can also see why the film does not work for everyone. The exact elements which made me go 'that was fun!' are the same ones which will leave some other moviegoers feeling disappointed.