Honestly, there are so many good RPGs already around. So many independent publishers putting out awesome games, and more than I'm able to play. I'm not sure how to answer this one. Reading through other people's answers I've seen some great responses, such as a "Hitchhiker's Guide to the Galaxy" RPG, or people who've said that they'd like to see their own work-in-progress games get published.
If I were going to follow that last tactic, I'd say that I want to see my game Walkabout properly finished and published.
I guess one of the main reasons for wanting to get Walkabout published is because I know there is a deep and wondrous spirituality in Australian Aboriginal folklore, and it's so different to what I keep seeing in Euro-centric and North America-centric settings. If I could see anyone get that right, I'd be happy.