Dell may have said that Android 2.2 would be coming to the Streak before the end of the year, but it looks like they weren't including AT&T-locked Streaks in that announcement. According to an internal email that was leaked recently, Streaks that are on AT&T's network won't be upgraded to Froyo until the week of January 12th. The email is dated December 7th, so as long as the document itself is legit, then it looks like you AT&T Streak owners will be stuck with Android 1.6 for around one more month.
Anyone that owns an AT&T Dell Streak may be wishing that they had opted for an unlocked model instead, but at least there's only about a month left before the update arrives. Sure, Gingerbread may be the new hotness when it comes to Android, but just about any update is better than using Donut forever. Plus, Dell's new Stage UI will be coming along with the Froyo upgrade to keep you happy. That is, until the Opus One comes out.