These are the commands I use to update debian and ubuntu:
sudo apt-get update
sudo apt-get upgrade
I thought that since I didn't upgrade from the old crunchbang to statler, it isn't necessary to do a dist-upgrade.
I installed #! from a memory stick using unetbootin (no cd drive in my netbook), and the debian installer didn't find any wireless networks, so I skipped the network configuration during installation. Then I configured the network after installation, and i uncommented the security.debian.org lines in sources.list. (Those were the only ones in sources.list except for the cdrom, and they were commented out because during installation, there was no internet connection and they were unavailable.) After uncommenting them, I ran cb-welcome. It installed updates from security.debian.org, but didn't add the right repositories to my sources.list file.
Then I started seaching what the right repositories would be, and I added the debian squeeze repository. I couldn't find the url for the crunchbang repository, so I didn't add it. Then I executed the commands listed above, and this broke the system (nm-applet didn't work, grub screen was different, gdm was different, some black spaces in the system tray, and the installation even hung, so I had to kill it. That was of course because the crunchbang packages were being overridden by debian squeeze ones.
Now that I added the crunchbang repository as well, it is safe to update, right? With the apt preferences file, the crunchbang packages shouldn't be overridden, right? I'm still waiting for confirmation before updating, because I don't want to install it all over again 