I have just found 2.1.9 from the market.
It appears "media button stealing" issue is fixed with Winamp (I use it as default local audio player).
The main point is the independent streaming engine.
If you don't have aac+ station or your machine runs on either 2.1 or 2.3.4, you don't have to enable it because it's not that stable right now (choppy with some devices even with 3G/4G or wifi). I didn't check the CPU usage but I found Galaxy Tab runs fine with the engine while some other phones have problem (MyTouch 4 and Optimus Virgin).
Update: the internal streaming engine works perfectly with G2x.
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