tabs

To borrow from web design: semantic meaning. If the tab character (following newline) is taken to mean "indent" then four levels of indentation is literally 4 tab characters. I use tab to align the '=' following a field alias. In this usage it means align the equal sign to some visual column for the purpose of readability. It would be great to have the IDE understand this convention and implement it without requiring me to use multiple tab keystrokes to compensate for longer/shorter field aliases.

I feel that a space should be reserved to mean a literal space character.

I also agree that it's largely a non-issue when beautifiers can reformat valid code into any visual presentation you want. In that case the code is actually reparsed and any original whitespace is irrelevant.