Signweb is my favourite site right now. For some reason, stuff that I’ve read a million times about visual design, usability or wayfinding just seems so much fresher when recontextualised by a site that’s also trying to sell me giant plastic-engraving machines.
This article has a great little colour-combos-for-legibility panel on page two:
Can’t Your Read the Signs?: Graphic layout effectiveness is measured in seconds
On a related tip:
“From small electronic objects to large airports, color plays a powerful role in helping you use the device or navigate the space. Unfortunately, color is only beginning to gain recognition as a critical component in “usability.” The following information presents a few of the many ways color can succeed or fail.”
Petafloptimism 