I know a few people in Ireland with micro businesses; a lot of them would file themselves on the revenue service's website. Some would pay an accountant. They do need to file, though, unlike most PAYE workers (ie normal employees).

You still need to do some kind of yearly accounts for your business. And you will most likely need an accountant for that. But the actual tax filing is fairly simply.

Couldn't tell you, since I'm a wage slave. But I hear Denmark is quite small business friendly, despite us being taxed up the arse.