After cycling a salt water tank, what should I add first fish,soft coral, or invertebrates?

It depends on what species you want to add, and your tank setup and husbandry skills. I personally would add some invertebrates first, like hermits and snails, as you are sure to have an algae outbreak after your tank cycles. If something is still amiss with your water quality, then you're not out much. Next I would add some hardy fish, and after a few months of successful fish keeping, maybe some hardy corals.

do you have your LR and LS in the tank? and good lighting for the corals you are wanting.

what kind of fish do you want?

depending how what fish and corals you want you need to put corals or fish in first.

put what you care about most in first, fish or corals and build that rest of the tank around what you want the most (REMEMBER TO CHECK IF FISH AND INVERTS ARE REEF SAFE!)

as long as you are sure that your tank has finished it's cycle and that you have plenty of the needed nutrients for each species you should be fine with either.

Please check out this web site before you spend and loose any money, and research each species you plan on getting ahead of time so you will know what each one needs.

http://www.liveaquaria.com/default.cfm?siteid=20

good luck