I noticed a similar issue after upgrading to ICS - CNBC videos would no longer play on my phone. I could only download them. I found the extension of the video files as .m3u8, so I searched on the Play Store and found VPlayer, which supports this codec. In "Settings-App Associations", I changed "Streaming Link", "Online audio downloaded by webview" and "Online video downloaded by webview", from "Streaming Media Player" to "VPlayer" and all is working again.
Still, I was disappointed to lose functionality by installing the ICS upgrade. I've also noticed editing text has become funky. In GB, I could place the cursor at a location and then delete anything in fromt of it by pressing the backspace key. In ICS, sometimes letters after the cursor get deleted (or in some completely random area of the text), leaving the text in front that I wish to delete. But sometimes deletions still work like in GB. I work around the issue by selecting entire words and retyping them, but this is annoying.
I also experienced choppy video playback from my Surfline.com Surf Cams, which ran without issue on GB. Using VPlayer, Flash, Chrome, Dolphin, and Maxthon Browsers, or Surfline's Android App could not change the poor video playback behavior. I broke down and did a Factory Reset from the HBoot menu, and experienced no changes in any of the issues I experienced after the ICS update. I was not surprised, since the ICS update downloaded clean and installed without issues.