2.6 is out since a week ago, to soon after 2.5.1.

A couple of added features, that I really like and will be very handy.

Track Revisions: You can now track changes to every post and page. When you edit a post scroll down and click on “Post Revisions”. You will see all your changes you have done to a post and be able to click and compare any 2 revisions.
If you like revert an old revision, you can restore it, and bring it current.

Theme Preview: The other feature that I really like is previewing your theme. I know you can see a lot of demos of themes, but I usually upload a lot of themes and this feature will let me preview the theme with my content, before activating it.

Word count: Word count feature displayed on the right hand side under the “Save” button.

Added Security features that are worth to consider:

– Admin SSL support: WordPress 2.6 admin can be accessed via normal connection (http) or now SSL( SECURE SOCKET LAYER) which is encrypted and more secure (https), with the option to make admin (https) mandatory.

For taking advantage of SSL connections, you will need to acquire a static IP address and buy a SSL certificate. It is affordable at godaddy.com and I can help you set it up.

– XML_RPC publishing protocol disabled by default: By default installation these features are disabled. If you need to use them, then in your admin area, you will need to go to Settings and choose the “Write Page” option to enable these features.

Check the official video for more features.