having the diff. date formats is a little dangerous indeed -- but thats my little 'sanity saver' test. i ended up killing the unix timestamp format, as i found mysql's datetime to be faster for my needs

at least on my operations, getting all the info for a 'day' was much faster matching the left 10 characters in mysql to a 'yyyy-mm-dd' date than was searching where 'timestamp > daystart AND timestamp < dayend'

to insert a date, i just do a 'FROM_UNIXTIME(time)' - and mysql could either spit it out as a yyyy-mm-dd or TO_UNIXTIME