Personally I find sugary soft drinks are not refreshing as all the sugar makes me sluggish after less than a litre, and I don't like the taste of diet versions. Eventually, I think I found a good comprimise:
I buy low calorie Lemonade from Coop or Grapefruit (Zero) from Denner. (you cannot buy the former in Denner and the Coop version of the latter is not as good as the Denner version).
Then I mix with the lemonade with cheap orange juice The result is like Orangina. Lightly sparkling, not too heavy or fattening so you can drink plenty on a hot day.
I particularly like the Grapefruit version (Grapefruit Zero + Real Grapefruit juice). The fruit juice hides the taste of the artifical sweener, and the drink is lightly sparkling instead of flat. And also is pretty low in calories and sugar.
Then there is the good old fashionned Apfelschorle - popular in Germany, a half-half mixture of Apple juice and sparkling water.
I also found that shandy made from cheap German beer (Rheinheitsgebot) and low calorie lemonade is drinkable. (It does not taste as good as regular shandy, but is more refreshing due to the lack of sugar).
For chocolate milkshake, I put (unsweetened) cocoa powder into a bottle, and then shake it with milk to dissolve the cocoa, and leave it to stand for a few minutes. Sometimes I flavour it with whisky, coffee power, honey, almond liqueur, Amaretto, Cointreau or Batida de Coco.
Tonight (still on an experimental quest to quench my thirst), I put cocoa powder and orange juice into a bottle and shook it. It dissolved almost instantly. The result tasted like chocolate orange - I like it bitter.
All these drinks taste better chilled obviously.
There are good drinks available in Switzerland, but always quite expensive, and with a bit too much sugar.