My new favourite PC game is Just Cause. It's an action/shooter, but like nothing I've ever seen. There's no levels, or loading between areas. Just one massive - MASSIVE - world to explore. It's set in a fictional South American island country, where you're a spy who helps rebels overthrow a corrupt government. You can fly planes, drive cars, parachute about, hop in boats, jet-skis, and all sorts of other cool things. A fast way to get around is to shoot your grapple-hook gun to attach a line to the back of a passing car, then pull your parachute out, and parasail behind the car, down the street :) Anyhow, I made a slideshow of screeshots from my new favourite game, if anyone on here wants to see how it looks. I've spent more time just wandering around, exploring the land, than actually doing the main story missions.
http://www.imagewise.com.au/ss.php?fid=886