Yup, St Davids is a little city next to a really really nice beach

lots of nice walks and things to do (Pebbles is an awesome cafe)
Google for it

the beach is called whitesands beach!
Little city?
You mean a city with 12 houses?
OP, it's the smallest city in the UK, but don't let that put you off, it is a very nice place.
york or newquay my fav places in the uk
Newquay is a little built up and touristy IMO, Cornwall and southern Devon should definately be seen though, beautiful places and pretty easy to get to a lot of places by train/public transport.
Recommendations (accessable by train):
Penzance - End of the line (but you can get the Helicopter to the Isles of Scilly) but siuated in a very nice part of the country. Penzance itself is nice but it also has St Michaels mount and is only a shortish bus ride from Lands end and Cape Cornwall (Cape Cornwall is FAR nicer than Lands End!)
Truro - The "capital" of Cornwall and very nice to have a wonder round. It's also about 6 miles from Perranporth which itself is beautiful coastline and a bit like Newquay in the surfing stakes. It's also where the train to Falmouth stop, which is another coastal port with a lot of character and worth a wonder round.
The Eden Project (St Austell on the train) apparently worth a visit if you like gardens and giant greenhouses.
Newquay is accessable easily by train (don't stick your head out the window, really, I don't know how the trains don't scrape the tunnels and bridges on that line!) via Par.
As you'll be going through it its worth a stop at Plymouth for a day or two. The city itself is a bit bland but the seafront is very nice and you can get the bus up to Dartmoor which is definately worth a visit (
http://www.flickr.com/photos/wildaboutlife/sets/72157603753002273/ ).
The whole of the north coast of Cornwall is pretty much the same, all beautiful, so definatly worth a visit. A few photos I've taken of that coast
http://www.flickr.com/photos/wildaboutlife/sets/72157619468861337/ , they should all be georeferenced as well.
Yeah I miss the south west, the south east just isn't the same.
