Spider Island stands at the top of the list, IMO. 
 
Schism is not really an event, so much as it is a prelude to a restructuring... although Generation Hope does get some mileage out of it.  I guess I think this is an okay event. 
 
Fear itself is shaping up to be boring, but some of the side-stories are cool... all of the Fear Itself X-stuff has been tight. 
 
Marvel gets barked at for running so many events... but outside of continuity/timing issues, I don't see a problem with it if you can tell good stories.  The reason why Fear Itself gets dead last is because of the sheer number of tie-in books which suck.  But I think they'd mostly suck just as much w/o the tie-in... with the possible exception of Avengers, which Fear Itself should really be taking place in anyways.  Thor/JIM, X-titles, and a couple of the 3 issue minis have been fairly good.  And would have been good even without the event. 

Right now Fear Itself seems to be the Big Event, and it doesn't seem to be all that, The rest is boring.