Your choices are...
hdd.ddddd - Decimal Degrees
hddd mm.mmm - Decimal Minutes
hddd mm ss.s - Degrees, Minutes, and Seconds
Outside influences usually decide this for you. For example what format does the guide book, web site, or program use? Does your team or group of friends use a particular format.
My own preference is to use decimal minutes (hddd mm.mmm), when nothing is pushing me to use something else.