Agreed about the labels. The purpose of having labels instead of folders is that they are so much better! The Google engineers are the best in the world and Gmail could easily have folders if desired, but Google engineers agreed that being able to tag any email with any label as many times as you want is much better than just clunking around with a bunch of folders.

I did a summer internship at Google last year and we were told that many/most Google products like Gmail, which are perpetually changing, will stay in beta indefinitely, or at least until they are clearly the dominant product in the particular market. It's an interesting approach and it has certainly changed the 'beta' philosophy in software design. If nothing else, the fact that Gmail is still in beta makes all of its users feel (correctly) that more updates and innovations are just around the corner! (recent examples like Gmail video chat, automatic attachment reminder, and Google goggles come to mind)

By the way, I'm happy to see all the comments about Google Apps on here. Inside Google, we all used Google Apps extensively and it was actually a really efficient way to organize a large organization. Everyone's Google calendar was linked so you could book meetings very easily; a variant of Gmail chat was used to get in touch with anyone in the company who was sitting at their computer; Google Docs was used so that employees could collaborate on a document without emailing around dozens of versions that all get mixed up; etc. I'm surprised more companies don't scrap Microsoft Office, Outlook, whatever Calendar software they use, and coordinate everything with the Google Apps suite...