I was surprised to see the old "You have 2 new comments. See your responses." top bar when I came to the site earlier today:
I don't recall having seen this for some time, with the global inbox having taken over. Also note that it was wrong, I had one new comment, not two. I'd already seen the earlier one. (And I think the global inbox got that right. I think it said "1 new comment" when I clicked it, but I can't be absolutely certain.)
Is the "new comments" top bar still active? Or did something hiccup?
Update: So below, Jeff said that it's still around and has been for a long time. And yet, I almost never see it. Today I came to SO after being away for several hours, using my usual bookmark as I did above. And you can see, the global inbox had SO comments highlighted (it had a red (3) before I clicked it to show them), but no top-bar appeared at all:
The rules for when it does and doesn't appear would seem to be non-obvious. It certainly seems anomalous.