As many have said, Vue will be the easiest to use, and it's renderer is very fast. If you are interested in modeling, and have a little more money, the base version of Cinema 4d might be the way to go. Neither of these programs support Poser 5 dynamic cloth or hair yet, though. Vue will directly import pz3's from Poser 4 or ProPack, and support for Poser 5 pz3s is supposed to be coming any day now in an update (still no hair or cloth, though).