With regard to .rsr files, there are 2 other .rsr files that get forgotten about too. They are both in the main Poser folder, Poser.rsr and Asiport.rsr and it's worth backing up the Poser.rsr and setting it to read-only. Deleting those two will probably break your Poser.

I also vouch for Poserworld, I joined pretty much purely for the scenes and felt I had more than my moneys worth as for me the rest was just gravy! :)