This is a little finicky request: in the original Post an Entry form, in HTML mode there's a checkbox to toggle "Disable Auto-Formatting" for the automatic <br> tags and such that get rendered when a post is published. This has been removed from the beta Create Entries page.

It's not a huge thing to have gone, but it does make it easier to give posts advanced styling if we have the option of turning that off (so that <td>s etc. can be visually separated a bit more instead of having a solid block of text to avoid extraneous linebreaks).