Google is making 4 major updates to its search suggestion feature. If you're not aware, Google Suggest is a list of keywords that appear in a drop-down menu when you type your query on Google.com. It was set as default on the Google homepage last August. The new updates will be rolled out gradually to new users.
The most significant update is the placement of links in Google Suggest. If your query looks like you're looking for a specific site, the actual site will appear in the search suggestions drop-down menu. This will streamline the process of such searches, reducing the amount of clicks needed to reach the end destination.
There will also be Sponsored Links in Google Suggest, which are search ads placed directly in the search suggestion box.
The other 2 updates are related to the actual queries.
If you're on the results page and conducting another search, you'll get search suggestions. The first suggestions to pop up will be related to the search on the current results page.
Additionally, Google Suggest will be injecting personalization into its suggestions. If you're signed into Google and have Web History enabled, Google will use past searches to provide search suggestions. The reason for this is that Google has found that up to 25% of queries are repeat searches, at least when it comes to users who are signed in.
Finally, one feature is being dismissed. The number of searches conducted on a query will no longer appear next to that suggestion. Google says users haven't found that data to be useful, though I'm sure SEO's and SEM's will disagree!