  We present a short overview of the properties of faint Galactic X-ray
binaries. We place emphasis on current classification scenarios. One of the
important parameters for the faint sources is their intrinsic luminosity. In
the case of low-mass X-ray binaries it has recently been realised that besides
a phase of radius expansion, the duration of type I X-ray bursts can be used as
a primer for the source luminosity in some cases. Further, we show that a very
low equivalent width of hydrogen and helium emission lines in the optical
spectrum alone is not a tell-tale sign for an ultra-compact system. Finally, we
list and discuss some unusual sources that could be X-ray binaries.
