I have downloaded WordPress 2.6 Beta 1  and installed it. Not much difference from WordPress 2.5 in terms of the layout.
Now on the extreme top menu on the extreme right, there is a link called “Speed up!” which links to Google Gears .
In the Dashboard, right under “Right Now”, there is a comment break down added to it. Here is an example: “You have 1 post, 1 page, contained within 1 category and 0 tags. Current comment break down: 1 total, 1 approved, 0 spam and 0 awaiting moderation.”
When you write a page or post, underneath the “Save” and “Published” button, there is a word count indicator.
The display of themes under “Available Themes” has also changed a little.
Now back to serious business.
I am still deciding whether or not to maintain WordPress 2.5 compatibility for the next wave of updates for my plugins as WordPress 2.6 introduces a lot of constants like “WP_PLUGIN_URL”, “WP_PLUGIN_DIR”
“WP_CONTENT_DIR”, “WP_CONTENT_URL”, etc.
2 potential issues that would break my plugin in WordPress 2.6 and I will be unable to fix it unless I find another way to do the AJAX, “Allow wp-config.php to exist one level up from WordPress root directory ”
and “Allow wp-content directory to exist in a custom location (not relative to ABSPATH) “.
Argh! WordPress 2.5 has the shortest development cycle!