Actually, XLS is not bad to work with, if you have a library for it. And it's well defined, unlike CSV. Insofar as I know, there's no way to make a CSV file tha

Actually, XLS is not bad to work with, if you have a library for it. And it's well defined, unlike CSV. Insofar as I know, there's no way to make a CSV file that will open and show nicely in all popular versions of excel / google docs/ open office, especially across language settings. And a well formed XLS file will just work.