While working through the guide I came across the problem that packages like ndiswrapper who work as a module to the kernel, will not work anymore until you recompile your kernel. Otherwise the kernel is compiled in GCC 3.3 and the modules in GCC 3.4. I think this warning should be added to the guide as more and more people are using wireless networks with ndiswrapper.
The following text has been present in the guide since its publishing: "Always use same GCC version for your kernel and additional kernel modules. Once you rebuild your world with new GCC, external modules (like app-emulation/qemu-softmmu) will fail to load. Please rebuild your kernel with new GCC to fix that."
