I love iCal- it could use some improvements like having the month written in large print across the top, but I use it on three macs all synched and hardly ever have an issue with it. My other preference is to be able to on ly have alarms go off on one of my three computers. also, for some reason when my wife's computer is not online it won't set off some of the alarms until she is back online at work. kind of sucks when I have an alarm set to go off on her off days.
Of course, I never use monthly view- too many things on my iCal I guess to use that view. I always use weekly.
One other thing I would like to see is a drag and drop addition where you could easily copy things off the to do list to a sticky sort of window to create a daily to do list. I know there are apps that allow you to have your dated to do things all on it or your events for that day, but i want one that you could customize by drag and dropping things- Anyone know of one?