Hmm, I keep it rather simple

- 2D Art: Photoshop/Gimp
- 3D Art: Blender/Wings/Others

And that's all, apart from an Engine (3DGS) that I use, sometimes also IceX2 for terrain creation. If you know how to handle e.g. Photoshop and Blender, you're able to create almost everything that you need. And naturally the forums here, that's the best "tool" for game creation.