[Amatenshi]

I use 3DS Max, and I rather like it. For my Technical Communications class in college, I wrote a tutorial on a lot of basic functionality, if anyone has the software and wants to get started:
https://dl.dropboxusercontent.com/u/4083...torial.pdf
^This covers a lot of box modeling principles, but as a side note, it's probably not good to use Generic Units for everything, since I made this model, at its low polygon count, for a Game Maker 8.0 game I made for a winter competition. It doesn't, however, cover texturing, because that's an entirely separate monster, and should probably be tackled in its own tutorial. I could try writing one, but I'm not exactly the best at unwrapping the UVs, nor am I a good source for texturing techniques. The principle isn't overly complicated, but due to the nature of the way 3ds Max unwraps, it can get frustrating sometimes.

If you prefer open-source software, Blender is a good one to use, but I don't know a whole lot about it. There's plenty of tutorials at http://cgcookie.com/blender

[Dismas]

I use Cinema 4D for 3D text, if that counts.

[Alex]

I like Rhino personally really easy to use and you can make really cool things