color palette for points, lines, text / interactive Rcolorpicker?

I don't know of any existing palettes that meet your conditions, but here are a couple of options for interactive exploration of colorsets (this is quick and dirty, there are probably some better orderings, base colors, etc.):

colpicker <- function( cols=colors() ) {
	n <- length(cols)
	nr <- ceiling(sqrt(n))
	nc <- ceiling( n/nr )

	imat <- matrix(c(seq_along(cols), rep(NA, nr*nc-n) ),
				ncol=nc, nrow=nr)

	image( seq.int(nr),seq.int(nc), imat, col=cols, xlab='', ylab='' )
	xy <- locator()

	cols[ imat[ cbind( round(xy$x), round(xy$y) ) ] ]
}

colpicker()


## another approach

library(TeachingDemos)

cols <- colors()
n <- length(cols)
par(xpd=TRUE)

# next line only works on windows
HWidentify( (1:n) %% 26, (1:n) %/% 26, label=cols, col=cols, pch=15, cex=2 )

# next line works on all platforms with tcltk
HTKidentify( (1:n) %% 26, (1:n) %/% 26, label=cols, col=cols, pch=15, cex=2 )


# reorder
cols.rgb <- col2rgb( cols )
d <- dist(t(cols.rgb))
clst <- hclust(d)

colpicker(cols[clst$order])
HWidentify( (1:n) %% 26, (1:n) %/% 26, label=cols[clst$order], col=cols[clst$order], pch=15, cex=2 )
## or HTKidentify

cols.hsv <- rgb2hsv( cols.rgb )
d2 <- dist(t(cols.hsv))
clst2 <- hclust(d2)

HWidentify( (1:n) %% 26, (1:n) %/% 26, label=cols[clst2$order], col=cols[clst2$order], pch=15, cex=2 )
## or HTKidentify

Hope this helps,