I use Carrara Pro for professional use. Given it's cost compared to other aps, I'd go ahead and get the Pro version if I were you. After you get the first full versions, upgrades are pretty cheap, so given what you get for your money, the inital investment will be well worth it and you will have an extremely robust, full featured ap at a fraction of the cost of the alternatives.

If you're looking to work with Poser, you'd have to buy the poser transport plugin if you went with standard, so you might as well go ahead and get the Pro version that includes the poser plug-in plus the other features of Pro.You might want to consider Hexagon as well if you do much modeling yourself.

The spline modeler in Carrara is pretty good. Although the latest verison offers a much improved vertex modeler, I still don't care that much for it. Hexagon is a great low cost modler.