Games are really expensive in Australia, so I have to think...is anything really worth $110 of my hard-earned cash? Well, I can think of some games that are.
Oblivion
Fallout 3
Mass Effect
And, I'm tempted to say, GTA:IV
All the other games I've bought that I would say are worth that much were from the previous generation and considerably less expensive, so it would be a much longer list. Those are just the Xbox 360 games I have right now that have been worth the investment. CoD4 would also be up there, if the campaign were just the tiniest bit longer - I want more of a good thing. =) And, I mean, Portal, obviously, so damn cheap on XBLA.