Whitchurch Common is on the western edge of Dartmoor – it is on the top of the hill before the land plunges down to Tavistock and beyond. There is a large car park on the Common below Cox Tor and it contains a plaque which details the panorama in front of you.
You can zoom in on the plaque to read the writing (i.e. double click on the image)
To help you I will transcribe the words / locations. From left to right (or if you prefer from south to north) it reads:-
Staddon Heights, Plymouth Hoe, Mount Edgecumbe, Roborough Down, Plaster Down, Tamar Bridge, Saltash, Whitchurch Common, Tamar Valley, Whitchurch Down, (Lands End 80 miles), Gunnislake, (Tamar Valley), Kit Hill, Caradon Hill, Kilmar Tor, Tavistock, Brown Willy, Launceston, Ramsdown, Brent Tor.
Here is a panorama of the view – you can double click the image to enlarge it – it includes all the places on the plaque and also includes Cox Tor on the extreme right.
Quite a view and worth a visit if your are in the area
A Dartmoor blog 
Also the best area for a sunset pic as well in my opinion. Go in mid-late June when the sun is setting right next to Brent Tor, a fantastic sight
I know it well. There’s usually a Willy’s ice-cream van there too.
Yup he was there