Currently, our installation of JIRA seems to use several different date formats:
November 16 - 4:00 PM (activity view on project)
Today 4:19 PM (issue creation/updated)
16/Nov/10 4:24 PM (issue comments, etc.)
16/Nov/10 (dashboard issues)
I would love to be able to set formats in my user preferences.
A lot of people who use my installation prefer 12 hour time, but I prefer 24 hour time. Some folks prefer "Nov 16 10", while others prefer "2010-09-16", and others prefer "16 Nov 2010". Add time into the mix and I could write examples for eternity. A few hate the relative dates (Today, tomorrow, etc) especially when they go into X minutes ago and don't update.