Well both made a big hit, but Spiderman 3 completely obliterated 300 in the office, even though I like 300 a lot better. 300 is one of my favorte movies and I pick it any day over Spidrman 3.
I hated all the Spiderman movies... and 300 was alright, but there are better action movies. it was funny, though, as SOON as 300 came out, a bunch of people tried fighting shield and spear at Amtgard. Sure, it works when there's a bunch of you in a wall, but did you notice that the Spartans all carried swords for when they step away from the wall? That's because the spear is a horrible weapon for single combat.
300, even though Spider Man3 started ages ago befoer 300, and has more comics, or whatsover than 300, I do say that 300 is better, because it has more action and, I think, drama to the story, and the people who made it work so hard just for us, unlike Spider Man here (Spider Pig is better! No offense, lols.)