Yikes! Ask three people, and you'll get three answers. I like Amapi (free version). A lot of people like Wings. A few do stuff in Anim8or. Then there are the ones you can buy with real nice bells and whistles. There must be a dozen different options for modeling, and to someone each is the best. I'd get the free ones, try them all out and see which one works best for you. Don't forget to get UVMapper for grouping and material assignment. THere's a free version of that too, though the Professional version is a great buy. One of the best tutorials is from PhilC available on his site. It's for sale on CD, but well worth the samll amount he asks.