Maps for everyone:
Ordnance Survey Explorer OL36 South Pembrokeshire Map. This comes in two varieties - the normal paper variety linked to here, plus an Active version that's a bit more weatherproof. The scale is 1:25000. Features are twice the width and height on this map compared to the Landranger, but the map only shows about a quarter of the area. (Available in Dial Cottage)
ORDNANCE SURVEY Landranger 158 Tenby & Pembroke Map. Also comes in two versions. The scale is 1:50000. (Available in Dial Cottage)
Map for North Pembrokeshire:
Ordnance Survey Landranger 157 St David's & Haverfordwest Map. There's a lot of overlap with 158, listed above. (Available in Dial Cottage)
For coastal footpath walkers:
The Pembrokeshire Coast Path (UK Long-Distance Trails). This is a full-on set of walking notes, and contains its own map. I think it's seriously worth looking at. Take care to buy the correct version of this book, though. Even if you're just dabbling with the coast visitors have found this a very useful book for planning. (Available in Dial Cottage)
Also:
Pembrokeshire Coast Path: Trailblazer British Walking Guide
Pembroke Coast Path (Route Map) A map of the entire path, printed on weatherproof foldable polythene.
Pembrokeshire South: Circular Walks Along the Wales Coast Path (Top 10 Walks: Wales Coast Path
Pub Walks Pembrokeshire : Walks to the best pubs in Pembrokeshire (Pembrokeshire: Top 10 Walks)
For cyclists:
South West Wales Cycle Map (National Cycle Network Route Maps
For climbers:
Pembroke Rock (Wired Guides) - 1000 Selected Rock Climbs
Pembroke: Rock Climbing Guide (Rockfax Climbing Guide)
For beachcombers and young botanists:
Guide to the Common Seashells of Britain and Ireland (Chart)
Key to Plants Common on Sand Dunes
Shells (Usborne Spotter's Guide)
RSPB First Book of the Seashore
Local interest:
Pembroke & Around Through Time
Local history:
Lamphey Bishop's Palace - Llawhaden Castle: Carswell Medieval House - Carew Cross