The only reason to render at a resolution higher than the standard 72 dpi is when the image will be put into print, etc. For viewing on a computer screen, it won't be worth it. Pixels are simply units. Like modeling, it doesn't matter whether you choose centimeters or miles. Both will look the same on screen, but quite different in the real world.

We don't know that x64 XP Pro is stable? Well, I guess I'm in early adopter syndrome. My Vista issues are over, and x64 Ultimate is doing just fine. Experiences along the way with 32-bit memory restrictions and rendering have done it for me.

Is quad core really necessary? I don't think so. The Mac Pro is a powerhouse graphics machine with its Xeon processors and plenty of memory, but in the end memory is king. Poser should be fine with 2 Gigs, but in reality seems happier with more for dual cores. Of course that comes back to the needs of the OS as well, plus other programs. Maybe much comes down to specific hardware/software setups.

Poser was not my first consideration when choosing a new machine. I've seen it finish renders nearly as fast with two cores as opposed to four (or maybe it was just me fussing with the tea). Applying huge muscle (and dollars) simply for Poser's sake isn't going to serve up much Satori.