Google added an ability to organize labels hierarchically – just go to Gmail Labs tab under Settings, look for "Nested Labels," enable it and click "Save." You'll then need to name your label with slashes (/) to make it the “child of another”. You can create complex hierarchies of labels, can expand/collapse labels, and be able to tell whether a given label contains unread messages by looking at whether it's bold or not. Please note this doesn't play nice with "Hide Read Labels" lab. You mightn’t get exactly what you expect if you’ve both labs enabled; for e.g., collapse/expand icons won't always appear when they should. Another highly requested feature ability to “preview messages” to get a glimpse on what they contain and maybe take immediate action without opening them. This’s exactly what "Message Sneak Peek" does. After you turn it on, right-clicking on a line in your inbox shows a preview pane with message in it. You can also use keyboard shortcuts for a faster sneak-peeking flow (enable keyboard shortcuts in Settings first if you’ven't done so): hit 'h' to open a sneak peek card, then navigate with 'j' and 'k,' and dismiss current card by pressing "Escape." Messages you peak at will stay unread (or it wouldn't really be a sneak peek, would it?).