Here on ux.StackExchange they have gaps that are a bit smaller than one line height (~88%), but I’ve read a few times that 100% of the line height provides best readability because it continues the grid of the text lines. I personally find the 100% gap a bit too tall. Does the eye even process these gaps as parts of a grid?
Your content will have its own tone, rhythm and meaning. One of the main jobs of typography is to help bring this out.
As kontur stated "it requires a visual eye and is always context-dependent". While it is true that the final choice should come down to your specific example typography is quite an old art and has a lot of guidlines.
While there are no hard and fast rules, these guidelines should help in most situations:
Typography is a subject that can (and does) fill whole books (and lots of them) and can take a lifetime to master. It is always worth getting a graphic designer or better yet a typographer to check what you have done - they will be able to quickly give you tips for improving your specific examples.
Some more reading for you: