honestly, unless you are going to have a lot of older children, spending money on an entertainer for 1 year olds is a waste of money. you would be better off just having toys etc for the little ones to play with or going to a place like a gym or playtown.
have fun! but remember, the party for the 1 year old is more a milestone for the parents than the child. the child has no idea what is going on and some children can get overwhelmed by large numbers of people!