The freeware program Art of Illusion http://www.artofillusion.org/.  To me it is more intuitive and easier to use than the others.  Things that some other people love like Wingz or Anim8tor, I find much more difficult to get into.  Ditto for Strata, Truespace, yada, yada, yada.  Modeling apps are, IMO the most preference prone type of program I've seen.  You may never find one you're really good with if, like me, you're 3D challenged, but one or two will probably just "feel" better than the others.  I've said many times that I think the developers can go a long way toward making modeling more accessible. 

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken