I was having intermittent problems updating a number of apps, including Angry Birds Seasons (from both Marketplace and Amazon AppStore).
I ended up moving all my SD-card installed Apps back to the phone. Backed up all my photos and videos from my SD card to my laptop. And then Unmounted my SD Card, Formatted it, remounted it.
Then everything that wouldn't update, updated. Moved all my photos and videos back. For now, I'm keeping Apps on my Phone, just in case.
Beat all the Easter levels immediately after and now I'm working on stars and eggs.