Hi

Suggestion

1) There should be option called --size in yum which restrict the space which be used yum. This would be beneficial to machine with low disk space.
2) If firefox 3.1beta is default then please have extensions.checkCompatibility=false
3) Shutdown splash screen
4) ext4 in grub

Observation:

1) Why logout is available at two different place a) under system b) In panel under name
2) Preference menu list is too long
 
Thanks for the great work.

Regards,
Sachin.