Orange = ghetto? that's new, lol.
The orange glow was an afterthought. I wanted to making something with a lot of blue paint (as inspired by GAFYs textures) - I originally hard a purple/blue warp grille, but the ship got way too heavy in the blues. So What i did was I took a look at the color wheel and thought "how far away from blue can I get? OH Orange!" I then tried it and thought it looked fantastic.
I have since adopted a similar principle for all my other textures. Start with a color (red, blue, green, orange, whatever) and a metal (gold, silver, white, platinum, bronze, copper, etc; yes white is actually a metal according to heraldric terms). and then pick a color that is opposite (or nearly opposite) on the color wheel for contrast.
So it ended up, for the Feds, being Blue as the color, White as the Metal, and then Orange for the glows. The Kzinti are Red for the color, Gold for the metal, and Teal for the glows (actually, cyan is opposite red, but its close enough). You should also note that my klingons are the same idea as the kzinti, except the metal is grey instead of gold and is the primary color instead of red being primary.