How to personalize your N900

Background images
Background images for the home (desktop) screens can be changed individually or all at once using background image sets.

The background image set is defined in a .desktop file [Desktop Entry] Type=Background Image Name=Deers Hidden=true X-File1=/home/user/MyDocs/.images/deer1.png X-File2=/home/user/MyDocs/.images/deer2.png X-File3=/home/user/MyDocs/.images/deer3.png X-File4=/home/user/MyDocs/.images/deer4.png X-Order=01

Themes
There device itself has a limited amount of Themes installed, but there are already a number of alternative themes available.

Transitions
Transition Control is an application which allows you to change various transition effects of the phone. Another approach is to edit the /usr/share/hildon-desktop/transitions.ini file

Device boot video
By default the device displays "Nokia Hands" video while booting up. it is possible to change the video shown during the boot-up or add additional videos in the sequence.

http://talk.maemo.org/showpost.php?p=347794&postcount=1

Resources
http://wiki.maemo.org/Maemo_Summit_2009/Day_2#Personalizing_your_Maemo_5_device

http://www.slideshare.net/hartti/n900-personalization