Although it's a city I believe, I do like St Davids.
Aberystwyth is nice and I used to like going to Lampeter when my brother was in university there. Wrexham was nicer than I expected it to be as well.
Tenby is great and I really enjoy the drive to Brecon - although I'm not a huge fan of my destination for some reason.
Loved visiting Abergavenny when Glamorgan used to play there as well.