Which would you think is the best software for molecular modeling?

That answer is highly dependent on what you're trying to accomplish.

 

I really like GAMESS as it supports all levels of approximation from simple "ball and stick" classical geometry optimization all the way to relativistically corrected molecular orbitals.

 

How much quantum theory do you feel comfortable with?

 

Many modeling programs are easy to use but the trick is understanding enough physics and chemistry intuition to interpret the models effectively.

Edited November 26, 201114 yr by mississippichem

As Mississippichem has already said, it will really depend on what your trying to do.

 

If you want to analyse X-ray structures, then something like Pymol is pretty good...although is not exactly friendly to new users.

 

For modeling small molecules, there is RasMol...but I have never really been impressed with it...