My top three are pipe dreams, but I'll throw them out anyway. Cypress Point, National Golf Links, and Augusta National. The first two are far too exclusive to allow the WGT team to shoot and neither will ever host a major to get on the list that way. I always thought Augusta would never be in a game, but now that EA Sports proved me wrong they have an exclusive.
If I'm being realistic, TPC Sawgrass, Spyglass Hill, and Muirfield Village would probably top my list. All are public courses (at least I think Muirfield Village), all three like attention (especially the first two), all have been featured in games before, and they all host regular tournaments. Slightly below them, but still near the top of my list would be Whistling Straits. Then they could replicate the perfect 2010 major season Augusta, Pebble Beach, St. Andrews, and Whistling Straits.
But really, if any of the first three could happen it would be amazing. Along with Pebble Beach, they are the best courses in the world and the opportunity to play them even virtually would be incredible. Even a cheapskate like me would be willing to pay for the opportunity.