WordPress Version 2.5.1 is already been released and is out now. It has an important security fix that is not been exposed yet but it will most likely be found soon enough.
Other fixes include the media uploader that has been the cause for many a blogger to revert back to previous versions. I haven’t encountered any of the reported issues on my test blog running 2.5 and I normally don’t encourage upgrading WordPress but in this case, if you are running version 2.5, you can grab version 2.5.1 at WordPress.org.