I've always liked the space orks from the Warhammer 40k universe. It's like a bunch of English football hooligans scourging space.
I must admit i've also started to really take a shineto the Ferengi after I rewatched star trek DS9, pure capitalism at it's finest!
I can't remember the name of the species, butThe traeki from David Brin's Uplift books there are a race of animal-intelligence ring-shaped organisms that could 'stack up' to form a sapient whole. An individual consisted of a particular arraignment of rings, and adding or removinganytoo many effectively created a new person.