I have got a complain regarding recent bug in the Linux kernel that Debian did not update the kernel using the latest one in security updates.
Release Notes is very important document that is not worst reading before installing new or upgrading from previous distribution.
Since the Etch release Debian has metapackages named “linux-image-2.6-arch” that always depend on the recent kernel package for your architecture in your distribution. So, if you want your kernel to be updated automaticly, you need to install the appropriate metapackage, for PPro/Celeron/PII/PIII/P4 it will be linux-image-2.6-686. If you have no such package installed, your kernel will not be updated even from security updates.
This is useful feature, however it seems that it produces a lot of human factor failures. So, if you prefer to update the kernel yourself (e.g. you have automatical updates and want to control the process, anyway you will have to reboot after the kernel update) you just do not install this metapackage. If you prefer the kernel to be updated together with all the other stuff, you need to install it.
If you did not read release notes you might have this package not installed, Debian still lacks telepathy support and cannot determine your intentions. Be careful!