Russia, hands down. So reverent, so solemn and yet triumphant, so Russian. The French one is great as well, really triumphant.
The US one is one of the worst imo, more for the way it's used than the actual song. Anthems are supposed to be sung by everyone and have a set tune, not by one person while everyone just stands their watching while they make it up as they go, warbling all over the place. It's not a singing contest, it's supposed to be about uniting a nation.
It's going to be really weird switching back to God Save Our King when the Queen kicks the bucket, it doesn't seem to flow as well as god save the queen and doesn't sound right. It's a dull anthem though, I prefer Rule Britannia, that's something that sounds right after winning something.