Well I voted ICC06, but that is only because I haven't played ICC2008 yet even though I am hoping to buy it soon. So it turned to a ICC06 v ICC3 for me, which is no comparison in my eyes. ICC06 is quick, easy to use, the user interface is nice, it's editable and it isn't a chore to do a season or more on it. ICC3 is quite the opposite for me though as it's slow, the actual graphics(not the players) is not my style, it's not editable easily and it took me too long to do a season on it. I prefer the old style ICC when they do the commentry like they all come at the same time quickly but in the newer version they come ball by ball which can sometimes lag and it takes ages.
I've got more to say but as I've got school in about 10 minutes, I better stop.