Still a little too glossy. Do you have to go in-game to check every little change? I don't know which texture to tweak- darkening the blue channel quells this but the bump goes with it. I'm fairly certain the glossiness is necessary for the height. Something more desirable might be able to be reached for a scaly surface, but I doubt it will ever work for something like human skin. Light maps seem pretty easy on the other hand, since it's faking the "reflection" you're supposed to see in a surface, a desaturated macro of the surface you're trying to achieve should do. For example the eye reflection used for a gloss mapped eye worked really well, but the clouds and skies commonly used for light maps will look ridiculous indoors imho.
The reflection map is supposed to be an image of the environment, modified by the surface material. If your material is plastic, it's reflecting everything, however there is a lot of loss compared to an ideal reflector so you mostly see reflections of light sources, i.e. the specular highlights. Other surfaces are microscopically rougher and scatter light in all directions, in the extreme this is like the smooth lighting in Morrowind where there is no change as you change viewing angle. The part in-between contains interesting things though, not too shiny, not too flat. You get there by blurring the hell out of the reflection map, a blur about 1/8-1/2 the size of the image. Because the texture wraps you have to tile the image 3x3 times so the edges blur correctly, then cut the centre tile out.
Wait, GIMP has a normal map filter? Why did I not know this? That's brilliant! I've been going crazy for lack of one ever since my 64-bit OS forced me to upgrade to Photoshop CS5!
I would use the one in the nVidia DDS plugin. GIMP isn't as accurate at generation.