Although on line banks tend to have less requirements and charges, it does depend on your circumstances. We use Cajasur, with a OK Plus account and if you can get your pension or wage paid in, and have at least I direct debit a month, and use your card so many times a year, there are no charges at all. Their website has all the info. My next bank account will probably be an online one though, as that's the way banking is going.
Hope this helps
Andrew