Try searching for 'keyword tool' and you'll see what I mean. The first SERP is actually showing as a search suggestion! This could be very big, as the #1 spot might now become more important than ever...
Why would Google do this? It clearly reduces exposure to ads. Unless they will start showing ads as search suggestions.
I've got a couple of comments. Contrary to the prevalent tinfoil theories, Google's first principle is user happiness rather than Adwords income. Adwords only succeeded in the market because Google's search algo creates happy users. If you've ever read Jim Collins' book "Good to Great", happy search users seems to be Google's "hedgehog concept".
So when a query term has a strong possibility of navigational intention, a link does show up as the top Search Suggestion.