A good recent summary of the work a game design "concept artist" is expected to do is at
http://www.imaginefx.com/02287754332...es-artist.html . A search of the same magazine's (ImagineFX) database also gives several other interesting articles on game design .
For a feel of typical work on core game engine software, take a look at the Irrlicht Engine site (
http://irrlicht.sourceforge.net/ ). It is probably one of the most capable 3D graphics/gaming engines around - and the current release apparently works both on Macs and PCs (C++ and .NET, but not Linux).
I'm only guessing at the ratio of "hard core" programmers to artists and animators for established gaming companies, but I suspect that it is at least 1:1, if not even more heavily weighted towards the artists, just because of the raw quantity of the graphic material that needs to be developed for a modern game. (How many of the "artistic" contributors started out as programmers, however, is a very interesting question.)