400watt would be fine, but it's hard to say if you'll need a chiller or not. It's something that you'd have to watch in the summer months, and if you need one, you need one. I would probably use a Mag9 or equivelant for the return pump. I'll be using a Mag7 on my 54gal when I redo that. A Reef Octo Extreme/SWC 200 would be a good fit for your system. Some people like ASM, but personally for the money you have to pay, I feel that there are some skimmers that pack a much better punch. The Gen II Vertex-IN series skimmers are also great. I'd go with a 180 for your tank.
I am in the process of getting my tank cleaned out and going to be moving as well, and I wanted to do a closed loop on my tank. I want to run a 400watt 20k XM with 6 24watt T-5's and a bunch of LED's. I'll have a vented canopy with fans, and a sump in a different stand with fans on that too, but I decided to go against the closed loop just due to the heat that the extra pump would put out. I'm going to save and get 2 Vortech MP10's instead! It's more money, but hopefully with the fans running on the sump and display, I'd be able to stay away from a chiller. Another thing that swayed me away from a closed loop was that I'm going to set up a mostly SPS system this time around, and using the MP10's will allow me to move them around and find the perfect flow, and when the frags get large, I'll be able to adjust the position as well. Plus the fact that they're controllable really sold me on the idea.
Not to say that you can't do a closed loop, but these are the reasons why I opted not to. On a 92g, you could probably run a pair of MP10's, but a pair of MP20's or MP40's would definitely be a better fit. Hope you have a good build, and keep us all posted with questions and updates.