It depends on where you live? for K-12 schools. Here in NW Ohio we tend to go the week before Easter or the week after.
With Easter falling early in 2008, were off from 3/21/08(Good Friday)-3/28.
I think alot of the Northeastern schools take their break mid-April no matter when Easter is.
I went to college at Purdue University and our spring break was one of the early ones back then. We were off in the time range of 3/8-3/15, which used to be the week before Ohio State(one of my BF's went there and we usually got to see each other over the lapping weekend).