Having enjoyed running the Starter Kit/Essentials Kit combo, I gotta say Phandalin.
When you combine the two kits, you get a real nice sandbox campaign that your PCs can use to go from levels 1 through 6 (maybe even 7 if you run "Sacrifice of Innocence" and go a little heavy with the random encounters). Plus, at the end, you can use Tresandar as the home base for your party, using profits from the mine to restore the manor.
It has the advantage of being close to a port like Neverwinter, meaning that you can get your party to Waterdeep or Baldur's Gate using ship travel (with nautical encounters - natch!) and there are enough other sites in the area to throw in some one-shots (White Plume Mountain and the Sinister Secret of Saltmarsh).
Couple that with the fact that Phandalin is still frontier-ish enough, you can control what the party does and doesn't have access to. Want to spend all your loot on plate mail? Too bad. Phandalin is a mining town. It doesn't have or need an armorer. Go schlep up to Neverwinter and have it made (and spend several weeks there while your armor is being crafted).
My general rule is to just use whatever last names are common to determine what a town has: Baker, Miller, Thatcher, Weaver, Chandler, Cooper, Turner, Carver, Carpenter, Brewer, Chessman (cheeseman), Bacon (pork butcher), Fisher, Fletcher, Gardiner, Glover, Ironmonger, Kellogg (‘kill hog’ a pork butcher), Mason, Slater, Spicer, Spurrier (spur maker), Tapper (wine merchant, Weaver Woodward (in charge of forests), Bowman, Shoemaker, Arkwright (chests), Boatwright, Cartwright, Shipwright and Wainwright (wagons), Calvert (calf herder), Cowherd or Coward (cows), Goddard (goat herd), Neatherd (oxen), Shepherd (sheep), Stoddard (stud of horses), and Swinnart (swine herd), Webb, Webber, Webster, Fuller, Tucker, and Walker.
The party won't be underpowered but they won't be overpowered either. And there's plenty of fun stuff that a crafty party can get their mitts on.