Just upgraded from 2.5 to 2.5.1 and all worked fine.
I was curious about the Google Sitemap plugin after what i ve read here but all seemed nice. Then again they say “curiosity kills the cat” so i run the debug feature that the plugin has and that’s what i found:
Errors, Warnings, Notices
Notice: Undefined property: stdClass::$args in ../../wp-includes/taxonomy.php on line 1068
Still everything seems OK but since taxonomy is one of the files that have changed i wonder if anyone has the same message and what really means.
Running on Apache 2 and PHP 5.2.5