Google Analytics, which is basically the former Urchin hosted on Google servers and delivered for free, is now available without invitation. You can see more information about the visitors of your site and analyze your performance. While Google Analytics had some problems that slowed your page loading and was even down for short periods, the service scalability has been improved. Google itself uses Analytics for most of its pages.
Google Spreadsheets, the service that allows you to create spreadsheets online and edit them collaborating with other people, is now a public beta. Although the spreadsheets have limitations and you can't add charts or macros yet, it's an interesting application, not intended to replace Excel.
The latest version of Google Talk, that includes support for file transfer and voicemail, will be released today, at Google Talk's 1 year anniversary. Although the client is not yet mature and it lacks basic VoIP features and a rich-text editor, the clean interface is a big advantage in the future developments. When Gmail will be out of beta (which is not that far away), the userbase will increase and the biggest problem of any messenger client (I don't use it because my friends / co-workers don't use it) will be solved.