I'm a huge fan of address labels. You may have noticed from past Christmas cards and party invitations that I almost always use them! I have all my addresses saved so all I need to do is change the design. To be honest, I'm not quite sure if Christmas cards would make it out without them!
I designed 2 different labels, one for cards and one for packages. You can even use a program like Photoshop, Photoshop Elements or GIMP to add in your addresses before printing or just write them in. I find it easiest to purchase full sheet sticker paper and then simply cut, peel and attach!