the following share- or freeware products are very suited for use in game development:
versions<0.6 are freeware even in commercial productions. Use Terragen to produce nice skys. If you want to sell your levels, buy terragen, or use terragen 0.6
Milkshape is perfect for low polygon characters modelling and animation.
for cutting AVI files and changing there codex.
changes nearly every 3D format into any other format.
is perfect for doing all texture work.