This won't 'kill' SEO sez one SEO blog, but it'll sure hurt it: that's the good news. The bad news: if things you don't like (Scientology, Sarah Palin, asparagus) keep showing up in your search results, it's your own damn fault. And if you're logged into Gmail (or any other Google Service... no, I don't have any Wave invites), you're logged in.
All Google Searches Are Now Automatically 'Personalized' even if you're not logged into a Google account (coookeees!). You can opt OUT (not a 'one-click' process, though).