As a boss of some sort of corporation, it really is going to come down to you to find the right presents for your employees. This is one job in the year that you shouldn’t leave to your secretary!
You obviously need to think carefully about how much you want to spend, and how you should spend differently on different employers, but try to remember that this is about seasonal cheer and not specifically about the contribution that has been made by the individual staff over the year. Because of this you should not be trying to reward those that have had great years. See it more as an opportunity to assert a little fairness and camaraderie amongst the troops. A decent present for everyone will make them all that little bit happier to be coming back after Christmas!
A great gift at a time like this is a Christmas hampers. A hamper is nice and neutral, and should be something that everyone likes. You will probably struggle to find out all of your staff’s tastes, so you should go for the sort of hamper which will keep everyone happy. Nothing too quirky, but something that has a bit of food, a bit of drink, and enough contents to show that you have at least spent a little bit of money! This way you will earn the respect of your employees, and with any luck, they will come back tro work after the Christmas break firing on all cylinders!