Palau is kinda unique, what with the jellyfish lakes, the Milky Way and even some of the dropoffs in the water you can see even on snorkeling.

Sri Lanka is safer than it was, but I haven't been since the tsunami. Would require a bit of adapting, but being a Buddhist/Hindu mix it's likely you won't be reminded too much of Christmas unless you seek it out.

Singapore is probably the lowest-hanging fruit besides Macau and maybe Taiwan.