New Gmail
I’m not one of the anointed few who have gotten to see what “Gmail 2.0” (unofficial name, apparently) looks like in person. I only log in to Gmail when I’m afraid there’s a server outage at home, or when I get one of those “check your e-mail and click the activation link” sign up things, and I’m not ready to wait the average 2.5 minutes of latency I incur by only syncing my mailbox with Gmail every 5 minutes.
With Gmail now supporting IMAP, I would have even less reason to use the “traditional” web Gmail. What’s still incrementally cooler about hosting IMAP from home is that I have an automatic backup copy of any incoming Gmail message stored on Google’s servers, in addition to the local mailbox copy and any backups I create within my home network.
As a web services provider like Google, perhaps the best argument for adopting IMAP support is that virtually nobody knows what it is, or why it’s better than POP3, let alone it’s improvement over a “rich” web client experience.
Heck, at this point you could possibly configure a webmail system hosted on a local computer to facilitate a connection directly to a Gmail account. So, basically you could have a skinnable Gmail.