Welcome to the forum.
A cube, I like those tanks. I probably would pick the 45gal just because it is not as tall and I can reach the bottom of it, I am not a tall guy so it is hard for me to reach all the way donw on a 24" tall tank. I don't know how tall you are but that is my view on that. If you get a sump you would want to get a better skimmer than the remora and one that can go in the sump. If you don't get a sump I am not sure there are better
HOB skimmers.
As far as the lights, is your 150w all you have? no other supplemental light? I think you may be able to use it if you do not get any SPS or any other light loving coral but I would be concern with the anemone. Is the anemone in a tank with that light? If you can keep it on your current tank and it is the same height as the cube it may still be ok.