This is rubbish. I am (was) a serial domain buyer. Now, I guess its somewhat true that buying a domain to go with your idea can really inspire you, I have a lot of domains I let expire or still hold on to because I haven't yet or never did anything with them. I don't think its a good idea.
Stupidly--I turned it down. I has such big plans. Now I keep it because it's such a weird word, and new people I meet remember it.