It depends on how much money and time you want to spend. There are a couple of free modelers that are decent, a few very nice inexpensive (<$200) modelers, a fair number of powerful midrange tools ($200-1500), and a few very powerful, extensible and expensive tools (>$1500). In general, the more powerful and expensive tools are harder to learn, as they give you more ways of doing something. Most have evaluation versions that allow you to see how they work and see if the work sequence drives you crazy. Cinema 4D, Rhino, Strata, Milkshake, Nendo, and Blender all have free or evaluation versions you can try. (There are proably others, this is hardly an exhaustive list.)