Its pretty unanimous that Spider Man 3 was pretty awful. I wasn't a fan of the first two that much either, but a lot of people did find them entertaining, they also garnered a pretty good response from critics, especially being a comic book movie.
In any case they say the budget for Spider Man 3 was somewhere around 500 million dollars. My question is how can a movie still be bad when you have unlimited money, and supposedly the best in the business at every position in your crew? Well the answer is simple: Story, without a good script or story all the money and effects and amazing locations in the world can't make you care about characters or get invested in the plot.
I bring this up because I saw Paris Je t'aime last weekend and it was absolutely amazing. The film is comprised of 18 short films all revolving around love in the city that supposedly oozes with romance. The shorts feature great directors like Gus Van Sant, Alfonso Cuaron, the Coen brothers, and Wes Craven, among many more. What is amazing is that many of these shorts in a few minutes could make me laugh, become upset (I don't cry cuz im a guy), and generally get emotionally invested, and this was in a matter of minutes. With a fraction of the budget of Spider Man a beautiful and great film was made, and purely because of its storytelling.
It just goes to prove that all the smoke and mirrors in the world don't really matter when you don't have the substance supporting it.