Head over to Godisageek.com to check out my top-ten list of classic Adventure Games that I think everyone should play. They are not necessarily all the greatest examples of their kind - but come with my highest recommendation.
If you haven't played any of the games on this list - track them down now as you owe it to yourself to experience the excellent storytelling and game worlds created by them all. They will all make you remember why you love Adventure Games, or help you fall in love with the genre.
Check out the full run-down here.