One of the most useful Google Suggest features missing from Google Instant was the Web History integration. Google Suggest used to show a list of previously typed searches if you were logged in to a Google account, so you could quickly select the query without having to type it again.
This feature is back in Google Instant and it hasn't changed too much. You'll still see up to 3 suggestions from your Web History, but the "Remove" link is more visible and personalized suggestions have a different color.
Unfortunately, Google's implementation is not great because it shows too many suggestions from your Web History and your previously typed searches are very likely to become predictions. For example, if you've searched for [Microsoft Tellme] two days ago and you now start to type "micros", Google will display the results for [Microsoft Tellme].
4 hours ago