Gamestudio= Reliable game engine to run your game, model editor, world editor, and lite-c script editor. Essentially, all you need to create a descent game. Throw this in with GIMP (FREE) to create textures, and BLENDER (FREE) to create some descent characters and entities, and you're good to go.
Maya= Professional modeling software to create 'next gen models' to add to your GameStudio game. Used to create Resident Evil 4, and SOCOM CONFRONTATION for the PS3. (Other programs were needed of course).
Either way, YOU WILL NOT be able to create a 'next gen' game that can 'compete' with HALO or SOCOM by yourself, or with a light-wallet. Dream smaller

Make a simple game just to say you made a simple game. And then, take it from there. Hope this helps!
-Kravenwolf