Flying. Old and not overly imaginative, but having played so many games with super powers, I fucking rage that there are next to no games that do real flight. In fact, the only game I've played where you could fly and it worked brilliantly (Iron man games were crap) was a mod for Just Cause 2. That shit was glorious, and it felt amazing to glide over icy mountains, deserts and massive swaths of jungle.
And then to make it even better, someone released a first person mod. So, combined that with flying, and all on a massive TV with me sitting not three feet away...it's the closest I'll ever get to flying.