MORE about gEDA:
Put new parts in /usr/share/gEDA/sym/local. That way they're available globally without having to put an entry in a gafrc or the like. If you need parts just for one project, then a /symbols in the project directory, with parts in that, and a gafrc local to that project, makes sense.

Don't give a component a refdes of power, or pwr, or ground, or gnd. It messes with the netlister. The component will come through but it won't be included in the netlist so it'll show up with no rats.

The pcb netlist is straight ascii so if you need to fix something broken by the above -- if you really truly require a connector named power -- you can just stitch it in to the netlist by editing it.

The netlister includes a surprisingly comprehensive drc checker called drc2: it'll flag some surprisingly obscure problems.