So glad that you got it!!
Most PSP users will say that they love and still use version 8 a lot!
(I never used that version)
I personally would recommend versions 9 & X but only if you computer is a newer, bigger computer as these large image files will really slow you down once you get the newer versions of PSP.
9 and X are a little hard to find at times, but if you google for a sale one usually pops up somewhere and you would qualify for the upgrade version I do believe, to either of those two versions.
I wouldn't do XI at all, but I have heard that they supplied the patches that fixed a lot of the issues.
As with any of these versions make sure you get all the updates for your version from the corel site.
Nothing has changed to greatly so where if you did upgrade that you would be totally lost. Yes icon will be more real looking, the tools are better, more choices for a lot of things but all in all still the same great program.
I like version X because we now have little icon in our layers palette so we can actually see what is on a particular layer which is really handy for a visual guide.
XI and X2 (the newest version 12) have paint brushes which are now 1000x1000 pixels big whereas the older versions only have the size of 500x500 which isn't the greatest it you like big brushwork.
I am sure some other PSP users will chime in here also with their advice and opinions!
If you have any other questions please ask them!!