Flyboy,
I've had nasty results with printer ink - it's fairly aggressive - sticks to everything and was hard to wipe off - ended up stripping the model and repainting.
I've used India ink with good results - I also will coat acrylics with Future, then wash with thinned enamels. Works pretty well..........
Oils are also a really good option - there are lots of colors that won't give you that stark, intense color differential that black gives you - depending on the topcoat color, use dark gray, burnt umber, or burnt sienna.
Cheers
LeeTree