If they're big ones, I'll try to put them outside. If they're poisonous, like a black widow, brown recluse, I'll kill them. If they're small ones all set up in a corner, complete with web, I will leave them alone for a while. They are natural pest control; the debris on the floor under their web are bugs they've caught and eaten. They are earning their keep. I say- job well done.

Put them outside so they can keep other bugs out.

Definitely not kill them. Spiders will not attack you for no reason. In fact, they help you keep your house clean from bugs and flies. Whenever I see some small spiders setting up shop in my room, I leave them be because they help to catch annoying flies and bugs. Sometimes I'll feed them myself if I caught one.