I installed ubuntu 11.10 on my notebook, and use gnome shell instead of unity. But after I remove all unity related packages, I found I lose my splash screen when I logout.There's only a command line interface which I cannot re-login again.
Anyone knows which package(s) should I install to get the splash screen back? The packages I removed are here:

unity unity-2d-places unity-2d unity-2d-panel unity-2d-spread unity-asset-pool unity-services unity-lens-files unity-lens-music unity-lens-applications gir1.2-unity-4.0 unity-common indicator-sound indicator-power indicator-appmenu libindicator6 indicator-application evolution-indicator indicator-datetime indicator-messages libnux-1.0-0

Thanks for any suggestions.

And I also got a weird problem on 11.10 which is when I leave my notebook for a few seconds without any mouse or keyboard input, the screen will become brighter. I think it should have become darker for saving battery.
Any one knows how to set this function? Thanks.