Oh God so many! and of course we only know the ones we know. I'm also very familiar with Lewes. I agree a very nice vibe, individual shops, cafes and restaurants, plus one of the oldest bookshops in the kingdom. High up is the Norman castle presiding over it's town. Further down, Anne of Cleeves House, and a pub where the Gunpowder Plotters met all surrounded by the beautiful South Downs It does have a steep hill in the middle of it though connecting the two halves of the town. So that's Lewes moving on.
Lately I've fallen in love with South Hams, Devon, so my nomination would be Dartmouth, so so pretty, The River Dart running through it and much of what Lewes has to offer plus fish restaurants. I love it.
Plus we're often up in the Cotswolds visiting family and friends, which is awash with pretty little towns and villages too.
I remember Saudersfoot, lots of coffee shops and surfer dudes. Beautiful beach. Less heaving than nearby Tenby.
Further up north Harrogate, a gem of a town which has lovely shops and restaurants and even better Betty's Tea Shop!