If they dont shoot me first, and want to talk, I will talk. Especially if they are higher tech!
I have had a couple of games where the NPR's actually traded me (gave me) tech. Most of the time, they give me missiles, business end first.
Low tech races are good for a while to generate trade income, and they dont spam ships, so thats worth keeping them around for a while. They usually end of joining my empire though, once their trade value declines.
Friendly aliens that park massive fleets over my worlds and cause huge lag, tend to get shot.....