4 space or 1 hard tab more comfortable for me.
but I really wonder if there’s some kind of standard.. for WP theme-ing or in general.
http://blog.logtalk.org/2011/03/coding-guidelines-and-the-spaces-versus-tabs-holy-war/
http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#whitespace-1
http://lxr.linux.no/linux/Documentation/CodingStyle