I've noticed that many people get "Mounting Local Filesystems ... Failed" at boot when trying out their newly-compiled kernel and so did I. Here's a tip that worked like a charm for me.
It appears that the new 2.6 series kernels do not like the Enterprise Volume Management System (EVMS) that our beloved Breezy uses. So here's how to compile your kernel to avoid getting this error by applying the relevant kernel patch:
First, you need to install package kernel-patch-evms through Synaptic or apt-get or whatever you like to use. This installs the patch in /usr/src/kernel-patches/.
Then, before compiling your kernel, go to /usr/src/linux/, or wherever you keep your kernel source to be compiled, and run this in order to patch the kernel:
Then compile your kernel as usually and everything will be fine
sudo gzip -d 2.6-bd-claim.patch.gz
sudo cat /usr/src/kernel-patches/diffs/evms-bd-claim/2.6-bd-claim.patch | patch -p1
I tried this with a "vanilla" 2.6.14 kernel from kernel.org, applied the patch, and then applied the Con Kolivas -ck6 patch for enhanced performance and it worked perfectly.