I think Duncan has hit the nail on the head here really. I totally agree that conceptually using tabs for indentation is better than using spaces. Pragmatically though, you can't tell in an editor where spaces are used and where tabs are used.
Perhaps if editors colored the background of tab characters differently from spaces this wouldn't be a problem, or if Python was more restrictive and did not actually allow a mix of tabs and spaces for indentation there would be no problem - the compiler could throw out an exception for mixed characters. In reality, neither of these are likely to be implemented any time soon! The following quote sums things up nicely I think: "In theory there is no difference between theory and practice, but in practice there is." (No idea where I got that from BTW - someone's tag-line probably) -- http://mail.python.org/mailman/listinfo/python-list
