Kinda blew chunks.
Sure - there were some snippets that rocked, but they were mere wisps of symphony in a sea of rhythmless plot meanderings and tone-deaf dialog. Spiderman 3 seemed like it was trying to create some sense of depth, direction, and development - as previous installments did more successfully - but everything felt far too forced to be much fun. Too much motion (emotional as well as physical) into too little movie...
Wait for it on DVD, where there's a fast forward button, or if you must go see a movie on the big screen, try to find the infinitely smarter, funnier, and edge-of-your-seat exciting Grindhouse (best movie I saw this year), or the guy-flick adrenaline orgy that is 300 (Persian [dramatically]: "Our arrows raining down upon you shall be so numerous that they blot out the sun!" Spartan [laconically]: "Then we will fight in the shade...").