[belugacat]

> I think a simple piece of advice (stolen from Tuft) is to not use colors unless you really need to.

Funny, read your comment as my copy of Tufte's VDoQI is open to page 154:

"Color often generates graphical puzzles. Despite our experiences with the spectrum in science textbooks and rainbows, the mind's eye doe not readily give a visual ordering to colors, except possibly for red to reflect higher levels than other levels [...] Attempts to give colors an order result in those verbal decoders and the mumbling of little mental phrases [...] Because they do have a natural visual hierarchy, varying shades of gray show varying quantities better than color."