PoserWorld rocks. Whenever you are in that position of needing a thingamajig to finish your set... chances are you'll find it (or a close match) at PoserWorld.
Notice of new stuff is emailed to you, so you are always abreast of what's going on there too and you can correspond directly with the product creators, which is always good.
Ok, some of the older stuff occaisionaly has problems but if you let them know about it they will sort it out.
I think most of my renders contain at least one PoserWorld element in them and many are used again and again.
All in all, best bang for your money around, and yes, i have a lifetime membership.

Jack