Well the thing about B5 is that there is like so often in real life there is no really clearly defined good and evil.
Take the Vorlons and Shadows for example neither actually fully good or evil. The Vorlons represent a peaceful but stagnant existance. Shadows represent a violent but vibrant existance.
The EA are... Well just human... :lol:
The Narn are fighting the Centauri due to their enslavement, yet they use similar methods as the Centauri, subjugating other races and strip mining their planets.
The Minbari are mostly good but have a habit of turning into genocidal maniacs at the slightest provocation (I mean ok they fired on you apparently without warning and killed your big leader, but does that actually mean that they should be wiped off the face of the universe?).
The Centauri are typical of most Empires. There were probably some Centauri who thought they were doing their conquered subjects a favour...
The League are in fact almost exactly like the UN a mostly pointless talking shop, only good for heating your building (due to the enourmous amount of hot air they produce...).
Nick