For polygons? Radiosity is THE BEST source for lighting, but it takes up a lot of space. How much polys per scene should there be?
it cant be answered that easy like: ‘of course 42’ 
Rule of thumb: as view polys as possible with looking good so you have experiment. Polygons eat realtime but the baking process creates vertex colors so your object needs to be fragmented where shading happens. A plate with one or two polygons can’t give you a dramatic lightathmosphere with several shadows in vertexcolor mode
But in Space Guards I decided to bake into texture (with another software) and map it using UV mapping. Only additional coloring I did by hand in vertex color mode.
But in Space Guards I decided to bake into texture (with another software)
Could you tell us the name of the software ? Is it free software ?
No, pretty expensive but I bought a license long ago and so why not using it. I told already in another thread, its Lightwave which can bake very good. Difficult was to exchange models with intact uvmaps but I discoverd .obj files created and mapped with Wings3D (which is free) can be read by both, Lightwave and Blender, very well.
But I am pretty confident that the baking to texture scripts of Blender getting better and better!
You can bake color and lighting into vertex colors by setting the material color and then baking it. This is how the walkthrough demo was made.
Ya, but the dramatic shading will be lost. I guess I’ll have 50,000 polys tops.
I must say that I quite dont understand the last two postings but never mind. 50k polys are bit to much for my understanding, if you need so much detail you should consider baking textures which is also possible within Blender, there is one script included and I think some more are around and posted in this forum.
Cheers