I think it's probably cities. Yes there's more to spend on but once you're there there's generally more free stuff too. Galleries, museums, street performances, markets to putter around, open spaces to sit and have your picnic etc. If you can avoid the lure of the shops then there's plenty to do rain or shine. The countryside is free but it's not necessarily set up for fun times if it starts to boil or chuck it down with rain.
Cities require no equipment, you can wear what you want, just turn up and you'll be ok. Country requires proper footwear and things unless you want to look like one of those people who get stranded half way up the fell carrying your child in a rucksack wearing only flipflops and a sundress. The seaside is in theory cheap but for a full day it too requires equipment, at a minimum it requires a book or a dog, at worst it requires some kind of temporary structure to prevent burning and to keep the worst of the sand out of the tomato sarnies.
I fully realise that this is a biased train of thought as I am not a countryside person. Although I did walk through a field that had sheep in it in Scorton and was within 2 meters of a cow at Yorkshire Sculpture Park.
Despite Dan's nightmare Nottingham train trip this week I'm excited about tomorrow now that Red Spotted Hanky has helped me to get over my train doubts. The only downside is that I've just looked at the weather forecast - a broadly tolerable 22 here in Lytham St Annes a far-too-hot-for-me 28 in Birmingham. I look forward to your many air conditioned public buildings second city of England.