I'd recommend trying out a few different ones. Most of the modelers have free, older versions that are typically included on the CD's on 3D related magazines. Some can also be downloaded.
Some people prefer Maya, some Lightwave, some 3DSMax, some C4D. Personally, 3DSMax is the only program that made sense to me, so that's what I use
I've heard that both Truespace and Carrara are good programs for beginners. I used Carrara a bit years and years ago when it was still called Ray Dream Studio... but.. then I found Max
