And while I did not 'do' this officially in 1996, going off of memory suggests it was pretty static too.
I am thinking the last time an election markedly changed was 1992, and before that 1980. The rest from 1976 on, I think, were predictable in spring.
Of course, how to tell in spring if it is a year like 1992 or 1980 is pretty hard. :-)
I think this may get put to the test in 2008. My gut tells me Hillary! will have an overwhelming lead in the spring.
THe truly Red states will be even redder, and the truly blue states will be Navy blue. But I think almost all of the "swing" states will have a decidely blue hue to them.
2008 will be a tough campaign, and the GOP better be ready to bring the fight to HILLARY! in the summer and fall.