As Zyx says, for scoring, non-random.  For pure fun random is cool.

Sentient species taste better...

I'm sort of with Solam, except its not so much about avoiding things I don't like as ensuring I'll get what I do like, mainly a map that feels sufficiently 'galactic' to me--gigantic or immense, tight clusters, max majors, max minors, and moderately numberous habitables.

One thing I do avoid is the Drath, but that's because I both like super abilities in general and think Super Manipulator is just off somehow.