I've just got one problem after the Android 2.2 network. On my phone, the mp3 player skips when there's any kind of other activity on the phone that requires disk access. At first I thought it was related to network traffic, but then I noticed the same behavior when I was creating a directory and moving some files with Astro.
Basically, any time there's any kind of activity, even scrobbling the mp3 to last.fm, there's a skip in playback. This did not happen before the update, and of course I've checked the mp3s themselves. I did a hard reset and a complete format on the SDcard, just to eliminate those as possible fixes. I've used the stock player and the doubletwist player, both suffered from the skipping.