Saint David's Mall, browsing the world's oldest record store, visiting Cardiff Castle, going to the Cardiff Bay Opera House, finding a Welsh speaking pub and hanging out for good cask conditioned brew: these are few of the many things I've done in Cardiff, and I will return - hopefully many times.
Cardiff is a world class city in every way, and this is remarkable for it's size: 324,000 in the city, and 1.1 million in the surrounding area. Visiting from Ireland, England, or Scotland makes for significantly fun and cheap holidays. Last year I had the special benefit of being taken on a personal tour of the city by the recently retired city manager Byron Davies, who showed me the ins and outs of 20 years of renewal, and I am thoroughly impressed by this city of beauty, class, and absolutely no pretension.
For all the wonderful things Cardiff has to offer, there is no comparison to visiting during the pinnacle of Rugby season. During the 6 nations tournament downtown comes to life like no other time. The Welsh like their Rugby - sorry for the gross understatement - they love their "Rygbi."
If you like Rugby, you have to go to Cardiff in February or March for a 6 Nations Tournament event. If you do not, but have a close someone who does, Cardiff is a great city to be left on your own for a bit of sightseeing, culture, and yes - even shopping.