Vietnam artists have a good fusion of western and eastern art traditions. My guess is Vietnam is where the next pot of gold is.
The boom for Vietnamese artists have already happened before 2008. It was after the Beijing artist craze. With the recession, I'm not sure where the auction market is now.
The art market is about the same as any commodity market. All it takes to create a hype is good review and industry media exposure... Buy, hold for a few years, wait for the artist to hold a personal exhibition in NY/Europe/HK/Shanghai (or die) and then sell it for triple the price..
That said, Beijing and vietnam (HMC city) are historical cultural centers where there is a thriving art industry for young artists.
But for small time buyers like us, just choose something that looks nice in your living room enough liao.