How much money do you want to spend?

If you plan to render with Poser 8 and don't need it cheap, go for a Core7 Nehalem intel. Four cores with multithreading means eight threads for rendering. Combine that with at least 8 GB RAM and a 64-bit-OS and things should be great. Nehalems are a bit pricy, though.

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

Avatar image of me done by Chidori.