It depends how things pan out.
Avengers and Madagascar 3 will be have been out for at least a month pre the sequel so they won't affect it.
Wolverine 2 (is anyone really waiting desperately for a sequel to the first?) - either way, after the first didn't do that great it's probably not a major worry.
Now that Spidey is getting the reboot treatment they have to confirm they can get it out for then now they have to start from scratch with it all.
So the biggest competition (until more are announced plus always factor in an unexpected smash each year) would likely be Iron Man 3 and Batman if it's out - though I would have expected 2011 for that actually based on the three year pattern starting in 2005, but maybe they want more time for something.
'If the Apocalypse starts, beep me!' - Buffy Summers
'The sky's the limit.....' Jean-Luc Picard, 'All Good Things'
courtesy of Saquist