Are you referring to lighting kits as in studio strobes?
I always recommend Alien Bees for two reasons. They keep their resale value - a used AB800 goes for about $225 no matter how old it is. The second is that they are durable, and easy to replace if broken. A brand new AB800 is about $275. The output isn't as steady as something like a Broncolor or Elinchrome head, but for my purposes they are fine.