MathCAD is still around, it is at least pretty popular in my field (nuclear engineering). I actually hate it to be honest, but I think it is good for people who are less inclined towards programming.
That said, I think Mathematica does a much better job of notebook style programming. You can do some truly amazing things manipulating the Mathematica notebook. The language itself is also pretty nice, something like APL flavored lisp with M-expressions instead of S-expressions. It isn't without its flaws, but it is one of my favorite tools in the toolbox (along with Python, C++, Haskell and Fortran).
