if the skimmer you are planning on getting is one of those Berlin Airlift 60s you are just throwing money away, you would be much better off getting the considerably less crappy (but still not great) Berlin Prizm for around $75...its a HOB too so it will save you a bunch of room in your tank that that airlift will take up
might as well keep the HOB and run it empty just for water flow, no point in trashing something you've bought
add $100 to your list for lights and i think you will be on your way
might consider getting two powerheads (like one for each end of the tank) instead of one huge one