I don't know if I think that it is the worst ship, but my least played ship is the HWK. I never really play around with it. I've flown it once and it performed well enough, but to properly outfit one as a strong support ship it ends up costing too much IMO. I think the problem with it is that it's too weak to be fielded naked, and it is too expensive with "sufficient" upgrades. Even a simple Jan with Ion turret costs 30 points, and generally I'd want a dedicated support ship to be 25 or less. I bet I'll probably use it a little more in epic play, where I have more points to work with.
So what is your "Least Played" ship, and why?