After reading a thread in LQ, Eric decided to add grantlee to the deps directory of KDE 4.6 Beta 2 which should fix KMail sending problems and rebuilt kdelibs and kdepim against grantlee and thus it fixed another problem that i had which was a device was shown twice in KDE Notification area. Now, it should be displayed once only.
Also, Solid has been patched so it will not require HAL anymore. If your audio is still not working with HAL disabled, try to change the backend to Phonon (default is Xine) and see if it's working. You might need another package from Eric, which is phonon-mplayer in order to work with Phonon though. This is available from Eric's repository.
Kdevplatform and kdevelop has been upgraded to the latest development release and this is a required upgrade for those running KDE 4.6 Beta 2.
Happy hacking with KDE 4.6 Beta 2