The Baths are structurally beautiful and have a wonderful atmosphere, you get an audio guide that not only has lots of interesting information but also dialogue from the author Bill Bryson as you go round. All very well laid out and thoughtfully set out. At the end you can also sample the spring water (it is warm but tastes a bit funny LOL).
In the summer the Baths are open until 10pm which allows you to experience them whilst it is dark outside but lit with flamed torches - beautiful.
Within the Roman Baths is the Temple of Sulis Minerva, layouts of how the baths would have been in Roman times, information on all sorts of things such as heating, lighting, clothing, cooking and eating.
Definitely a must to visit if you go to Bath.
The city itself along with the Abbey, has the usual array of high street shops, but also lots of smaller independent ones such as a Christmas shop, hand crafted wares, specialist food shops and a huge amount of little bakeries and cafes including the famous Sally Lunn bakery. which is in one of the oldest houses in Bath and also opens in the evening as a very nice restaurant. The Minerva chocolate cafe is worth a visit too ;-)
Plenty of museums to visit or take a tour on the open top tour buses that travel around the city, a walk through the lovely gardens or a boat ride down the river.
It is truly one of our favourite places to go to.