[DonaldM]

It really depends on what you want to do. All the VI's that come with PT 8 are good and have great usefulness for different kinds of music. I like Xpand2 a lot and use it often. I also like Structure Free a great deal and Russ K and the AIR USers blog have made some unbelievable samples available for it.

ANd ou can use VST plug-ins with a VST wrapper program. Most here would recommend FXexpansion's VST Wrapper program. It allows you to use any VST plug-in or VI right in PT.