The 120 would be the best option. As it has deep front to back. Nice footprint for your rock work. I regret doing a 55g. Do some research before you buy anything. Get all your rock at one. Every time you add new rock, it will start the cycle over. Get a good skimmer and set up a refugium with a sock filter. You can go with T5 lighting or LED. Don't need a MH light, those are out date and would require a chiller. If you go with T5 go with a 6-8 bulb set up. If you go with LED, get a reef compatible system, not the one that are sold at Petco/Petsmart.
Once you have your rock set, let it cycyle for about 2-3 months before adding anything live. Weekly water changes. Get a good test kit. After 2-3 months start adding your cleaner crew. About 5-6 months you can start adding fish and corals. Don't add to much at once, as this will spike your amonia. After 5-6 months you can drop your water changes to every two weeks.
This is exactly what I have done and I had no problems. Best to use RO/DI water, it will reduce the algae breakouts. Also you can hook up a phosban reactor in the refugium.