Previously, I compared ChromePlus and SRWare Iron. Today, I think ChromePlus is better. Google Chrome 6.x beta already released. But SRWare Iron still using Chromium 4.x. That is why, I tried out ChromePlus, which uses Chromium 5.x. And there is no problem to play the WMA files. So, I choose ChromePlus now.
Besides that, there is also Linux version for ChromePlus.