It depends on your intended usage. I don't own Pro Pack myself, so I'm going from memory as to its features. If you don't plan to use other programs, that would be one reason to not buy Pro Pack, as one of its big features is the ability to host Poser scenes in other, more expensive programs, such as Lightwave. Pro Pack offers motion blur to create more realistic animations...but if you plan on using Poser for still pictures or more cartoony animation, maybe that's not a big selling point. Are you thinking about using some of the free 3D modeling programs to create your own special Poser characters? If so, it's easier to set them up with Pro Pack. Pro Pack allows mutiple views of a scene on screen, which is another animation friendly feature. Pro Pack also allows you to export your output to web-friendly formats like Flash. Match these sorts of considerations against what you want to do with Poser, and it may help you decide whether you want or need Pro Pack.