This guide will show you how to login to a Debian image and start LXDE by simply powering the Pi on.

Auto Login:

In Terminal:

sudo nano /etc/inittab

Scroll down to:

1:2345:respawn:/sbin/getty 115200 tty1

and change to

#1:2345:respawn:/sbin/getty 115200 tty1

Under that line add:

1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1

Ctrl+X to exit, Y to save followed by enter twice

Auto StartX (Run LXDE)

In Terminal:

sudo nano /etc/rc.local

Scroll to the bottom and add the following above exit 0:

su -l pi -c startx

(where pi is the username you want to run X as). Press Ctrl+X to exit, Y to save followed by Enter twice.

(Note: The previous method indicated that you should add startx to /etc/profile. The updated method is better, since it will cause startx to run only when necessary, and it will not launch the X server as root.)