Big Jim at Galaxy In Flames, has been making some interesting posts about problems he has been seeing in how people put together lists for Kill Teams, and it got me to thinking about what I think makes a good Kill Team.
To some extent, I agree with Jim, a small elite force 'in the spirit' of kill teams so to speak. While it is certainly possible to make a 'horde' list with as many as 20 figs or more, the game seems to be more fun if run at ten or less. The only time I have even hit the double digits was when playing Eldar rangers a few nights ago. Aside from that, the game is really more fun and friendly around 5-7 models per side.
What I really like, however, is to use Kill Teams battles as a simpler version of the game Inquisitor, by having a story, objectives, and reasons for what you need to accomplish and why.
Recently, I have played the Night Lord list below (and won), the aforementioned Eldar Rangers (draw, called due to time constraints), and Inquisitor and Retinue. Of the three, the Inquisitor matches my thinking of a great killteam, because while not geared 100% to killyness, they do have a lot of story elements that can revolve around them.
Most satisfying to play...well, the Night Lords. I smoked those Assault Terminators. I smoked them good.