It all depends on what you want to do. I always like to make a larger quilt because I assume they will be throwing it on the floor for the baby to play on.
So normally I do a simple design, because I don't want parents to think, this is too pretty to put on the floor. I'm all for pretty, but I also want my quilt to be used. :)
I would LOVE to see a quilt 10 years from now in tatters knowing it was used and loved, then seeing it look like it hadn't spent an hour on a bed or with someone curled up in it. :P