Mathematics - Regression software for linux?

Hi all,

I've recently started working on a project that's requiring me to analyze large amounts of numerical data. I need to be able to fit my datasets to some fairly intricate (nonlinear) equations (polynomials, transcendentals .etc). I've been playing around with R (The R Project for Statistical Computing) but I'm not sure that it's exactly what I'm looking for. Regression seems to be a pretty small component of it and it really feels awkward to do anything that's much more than a polynomial in it (of course, it could just be that I don't fully know how to use it yet).

Does anyone know of any software that's made to do data analysis like this? On Windows there are things like Sigmaplot or Igor pro (which really are not ideal either, but they seem closer than R...).

Thanks in advance,

-Ben