Interactive plots in R?

Hi all,

As part of a research project we are creating a statistical software
tool and will be using R as the computational engine.  I was wandering
whether we should also use R for plotting.  R has a good plotting
flexibility and an extensive library of available plot types. However,
our application is supposed to give our users an advanced
look-and-feel as well. For the plotting we will therefore need things
like:
 - interactivity (the possibility to interact with the plot using a
mouse, e.g. select data points or data bars)
 - zoom / scroll 
 - custom colors for lines, data points etc. 
 - conditional formatting (e.g. data points above a given threshold
are red and bigger while others are regular)
 - possibility to draw marker lines, custom-color bands and areas 
 - flexible axes, titles and legends 
 - axis grids 
 - export to image files (e.g. BMP) in high resolution 
 
Does anyone know how many of these things are achievable with R, to
what extent and using which package?
 
Thanks in advance, 
 
Michal Blazejczyk 
Lead Programmer 
Genome Quebec