It really depends would you like to work in Poser or not. Poser creates 3D art and animation, while PSP is limited to 2D. Go and see at the galleries what can be done with those apps separately or combined together. Since you consider yourself a PSP pro, that means you do have some older version at home. Maybe it's time to learn something new ? You'll use PSP in connection with Poser sooner or later anyway - for creating textures, adding special effects, making pics from layers... And even PSP7 will do for this. Go ask for Poser for Christmas :D I was in similar situation - I had PSP7 for a long time when I got my P4, I had to learn everything from the start. Now I'm happy, using both apps. See my gallery (or actually any other gallery) to see what can be done combining both.

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Outdated gallery over at DeviantArt

Fics at FanFiction.net and Archive of Our Own (AO3)