CalcCenter 3 for students and novices costs less than a typical math textbook, but it actually does all the problems for you. Even old-time Mathematica users will find it convenient for quick work on smaller problems.
New functions make Mathematica 5.1 an excellent choice for developing new software, from molecular biology to business databases.
Dr. Frame3D offers instant feedback on the mechanical properties of your structures, and is easy to learn.
Research Systems' IDL 6.0 is the best tool of its kind at providing visual images that represent statistics -- it can turn radar into weather maps, MRI signals into pictures of a skull, and space X-ray signals into maps of the universe.