What size is your cage? I have a 2x2x4 cage and went with the starter system and added a second nozzle and the zip drip to it. The starter system can handle up to 8 nozzles so no need for anything bigger unless you are going to run a lot of cages.
i agree with Video Master! if you only have one or two cages, the starter kit will be just fine you can get extra nozzles to mist in multiple places in the cage if you like, thats always good when you have a larger cage.