Hi,
I'd like to put in my 2 cents worth for GPC. It is fantastic! I've been using GPC for the past few years and it has been an invaluable aid to my productivity. It meets all my needs (most importantly the support for conformant arrays and modules). My main area of research is in numerical general relativity and I have taught numerical methods to science students for a number of years. With the current lively discussion on the future directions of GPC I though it would be good time to make my own contribution by way of making some of my code available. It's a collection of numerical codes covering a range of standard numerical methods (root finding, interpolation, integration etc.) as well as some more advanced methods (multigrids, adaptive integrations, improper integrals, boundary value problems, genetic algorithms and so on). You can find the code at
http://users.monash.edu.au/~leo/software/pascal/files/GPCExamples.tar.gz
More information can be found in the README.txt in the parent directory.
Cheers,
Leo Brewin School of Mathematical Sciences Monash University Australia