Because this somehow makes me to post my response.
If this information is to be read by humans, I use 02-Mar-2013 09:58:43. The time part has a basically really universal standard (hh:mm:ss), and the date part is made unambiguous with month’s name and 4-digit year.
If this information is to be stored and sorted (yay anagrams) by computers, I use 20130302T095843. Screw readability.
If this information is for both to be red by humans and to be stored by computers, I think I’ll use 2013-03(Mar)-02 09:58:43. But I doubt I’ll ever use it.
I need something better to do. Oh ya, fixing FFF25.