The secret to dying Easter eggs properly is in understanding your dyes, and how they react with the egg. Now, your typical dark colors, blue, purple, green, do not, in general, do well if let soak for a while. They get streaky, and I have yet to get my purple eggs to actually come out looking nice if I keep the egg submerged for more than thirty seconds. Purple is an icky color to dye with, anyway; if you want purple, dip in red first, and then a quick dunk in the blue. It'll look better, I promise.
Yellow and orange will come out beautifully if you drop the eggs in and just leave them there- if you do a quick dye with them, they'll come out pale and nasty, so keep them in long for optimal colors. Red's a bit trickier; if you're lucky, you can get it to come out dark and intense, but if you want pink, that can work, too.
Any way you dye 'em, they're still a pain in the ass, though; and who actually likes hard boiled eggs, anyway?