If you have used hifi's raspbian-ua-netinst, the unattended Raspbian installer, you might run into problems with modules:
ERROR: could not open directory /lib/modules/3.10-3-rpi: No such file or directory
FATAL: could not search modules: No such file or directory
I fixed this problem with:
apt-get install git-core
apt-get install rpi-update
Note that this will also upgdare your firmware and the linux kernel!