Where debating everything under the sun is only the beginning

Any place that's within about 40 minutes walking distance can be reached faster by not using a car. Plus a car is extremely unhealthy. You're forced to sit still, you're forced to breathe fine particles and other junk, plus you're getting stressed from traffic. It's hard to think of a worse way to get around than by car.

I'm considering to get some kind of mountainbike instead of a citybike because of the lovely cobblestones all over the city.

I can warmly recommend the hybrid type of bicycles instead. More often people need to ride on asphalt for tens of kilometres than in an outright forest. A hybrid bicycle does both highway and forest reasonably well, even a pure citybike does both types of terrain reasonably well, but a mountainbike is a total waste of nerves on a smooth highway.

Perhaps simplest described as a citybike with shock absorbers.

A trekking bike is a hybrid with all the accessories necessary for bicycle touring – mudguards, pannier rack, lights etc.

Using a sturdy welded chromoly or aluminum frame derived from the mountain bike, the city bike is more capable at handling urban hazards such as deep potholes, drainage grates, and jumps off city curbs.

Mudguards, pannier rack, lights etc. are called accessories. It's standard practice here, most likely there too, to change and add some stuff upon purchasing the bicycle.

But a bike without lights -- that's practically the same as a bike without brakes.

Electric bikes apparently only supply augmented power up to 25 km/h, so just when you're starting to get going they cut off, meaning you've just got more weight to lug around.^[1] I guess they're better if you're out of shape or something.^[2] Someone like Lance Armstrong averages at over 40 km/h.

So called Dutch Bikes are seen nowhere else in the world, 30 kg plus trash made for 2 meters tall Dutch girls to ride at flat terrain. Forget it if you need/want a decent bike.

Nope. You go at 25 all the time, that's what makes the difference in terms of average speed.
Of course you live at a billiard table so you don't have such problem, I would like to see you going up to the Castle at 25 just with your legs. 

So called Dutch Bikes are seen nowhere else in the world, a 30 kg plus trash thing made for 2 meters tall Dutch girls to ride at flat terrain. Forget it if you need/want a decent bike.

Do you have Decathlon at your city? they have the best price/quality ratio at a very complete range of bikes.

Why? Where I live, it hardly gets dark during the bicycling season, day or night.

Edit: PS. According to traffic code, reflectors are mandatory. I have reflectors as required.

What is a decent bike? (apart from something with an electric engine)

I forgot about the fact that there's barely any night up north. Here it does get dark and there isn't such a thing as bicycling season. But it's true that you're significantly less likely to have to use your lights between April/May and August/September.

Here lights are mandatory after sunset.

I'd say that a mountain bike frame (not full supension), narrow tires, 9-speed, v-brakes and equipped with a rack and bags it's a very decent machine. That's what I use.

You don't have a bicycle season because you don't have proper winter. I don't even try to bicycle in snowdrifts. That's where a mountainbike with chained tires would perhaps work, but such a thing will never be in my plans, because in blizzard it's hard to even walk.

Why bags? Because you live on the road?

Bags are for things like grocery shopping. I don't use 'em, but they have definite utility.

Why bags?

I overnight in the forest sometimes when I feel like it, but always close enough to home, because part of the idea is to have no heavy equipment with me. Just to sleep off some frustrations on plain ground while letting nobody notice that I was away.

Do you live in this world? where do you put the money from the bank you've just robbed?