I've only spotted two types of spider in Switzerland so far, and neither of them appear at all dangerous... especially compared to the ones I used to find at home (like the Sydney Funnel Web) - still, letting the kids at school know that didn't help one of them, who was terrified by a harmless house spider inside the building today...

The vast majority of spiders only bite if bothered, but unfortunately if you can't spot the thing first, you can 'bother' it without noticing until it bites.

btw, after poking about on the web looking up European spiders, found two sites that may help: Demystification of the Toxicity of Spiders & Spiders of North-West Europe. Got a good ID on the spider that scared that student, and it is just a house spider...