Arrrgh, this is horrible. Google changed something again overnight, and now I can't even view what's in my inbox. It just displays a message, "No new mail!" (even though I got at least two new e-mails since last night, not to mention the thousands of unread messages...)
If I enter "in:inbox" into the search box, then it seems to work like normal. But I just hope it's not hiding anything...
edit - Oh, it seems to be working like normal now. Maybe it was just some glitch.