Australia is buying MRH90s, an Australian multi-role version of the NH90 tactical transport helicopters. The other leg of the NH90 program is the NATO Frigate Helicopter, which would be perfect instead of the SH-2G, it's just that work on the NFH has suffered some delay and cost overruns for existing customers. And purely looking at the specification/performance, I'd recommend the EH101/AW101 Merlin instead for transport, but as a frigate helicopter the NH90 seems more promosing.
I think the NH90 is the best option for the RAN, especially for platform commonality with the army/airforce.
I'm thinking MH-60R/S's though...the "Super Seahawk".
Like, why not the Super Puma, or Mi-something?
Both lack maritime systems & armament options. Mil hasn't produced a proper naval helicopter since the Mi-14, afaik. The options are NH90 NFH, Super Lynx, MH-60R/S, Panther, Merlin HM.1 (if not too big), or some developments of the Puma, Cougar, S-92, or the smaller AW and EC platforms, but I think they'll pick one of the shelf options.