Earth is paradise. That'd be very dull, IMO.
A planet-based series would be different, but go for something more like a colony on the outer edge of the Federation, either into the unknown or just a stone throw away from a hostile species. Give them a Starfleet field office to monitor the region, protect and serve, etc.
The colony could either be a brand new one, so you have the whole situation of getting things established and building a new home, or (if you wanted to throw in an element of mystery and danger) a planet that has been resettled, after the original colony disappeared--a bit obvious probably, but it does set up a long-term plot element to work with.
Commander Austin Harris, First Officer, Deep Space Nine (by FltCpt. Bossco)
8.01 - Darkest Before Dawn
(Chapter 8 added, 12/09/2015)