I've played several games in which I map out 250+ star systems and encounter several NPR's.
99% of the time I establish friendly relations with NPR's and they usually hang around a small patch of territory. Never expandining in a particularly aggressive or fast way.
Basically, I've yet to really meet an NPR race that actually posses a threat to me. They seem far too tame. Have I just been lucky and not found one that dislikes my government type or has a hostile aggressive nature? Or do you have to provoke hostilities with one in order to wage war?
I'd like to experiance fighting a prolonged conflict with an NPR were my fleets are challenged and my design's are put to the test. At the moment I have a game with two friendly NPR's who are sticking to their corner of space colonising a few neighbouring systems whereas I have expanded and colonised worlds in over 6 differnt star systems three of which had alien ruins and one was an uninhabited colony cost 0x world.
I'd like to hear some more experianced players talk about conflicts they have with NPR's were they were challenged and fought out prolonged conflicts as it seems to be something i dont have happen in my games at the moment.