Titanium backup covers your apps, but not the "operating system".
The usually recommended "OS" backup method is to use Rom Manager, but note that this does not backup the kernel. This means reinstalling your (e.g.) 2.1 rom-manager backup, over a (e.g.) 2.2 installed rom will likely have odd results, as the kernels will probably differ.
I *think* that the only way to make a complete phone dump is to use ODIN (or something similar), but I have never done this.
hope this (warning) helps, for what it's worth.
AoN