At the end of the day, you can make your game and have your main character a blue cube and the enemies all red cubes yet still of the programming of a master game in there.
To make your games look good however, as Torq said possibly a good modeller or texture maker. It all depends on the type of games you want to try and make, if its FPS then possibly cartograph to make your levels, if its open terrain then geoscape. There's soo many different programs out there which you may want yet don't necessarrly need to finish the programming side.
J
Hello!