Just because the idea of someone monitoring your domain name queries sounds paranoid, that doesn't mean it's not happening. My final tip? Buy a domain name of interest as soon as you see it available.
That's exactly the way I operate. Never have a domain-brainstorming expedition unless you're willing to buy the domain right now. And if you find a good domain, buy it right away - not a few hours later. Right now.
Also worth reading the HN comments on this.