Maybe Stellarium is for simple star-gazers like me and Google is throwing in 100+ other tools for the people who want to know more. But for me Stellarium is doing exactly what I like: showing and naming what I can see on a given bright night.

http://redspinach.blogspot.com/2008/03/google-sky-astro-gaze-through-your.html

First, many of the software programs you state, do not have actual sky data in them. They are, like planetarium data, a representation of the sky taken from catalog data or fabricated. Sky in Google Earth has real astronomical data. It took several years to obtain the SLOAN data and the Digitized Sky survey occurred only once.

Earth Scientists have all kinds of orbiting satellites. Landsat has been taking data of the planet for 30 years. Give us 30 years of continuous sky coverage with fleets of satellites and we will be able to bring you the same sort of nearly perfect sky data as you see on earth. OR…. use simulated data like the other programs if pretty is all you want. Hubble cannot possibly cover the sky at its native resolution even ONE TIME in 30 years.

We have an angular sky scale offered by my group at Space Telescope.
You can indeed add images using open source software, but stay tuned to the Space Telescope website, we will have something easy for you to use soon.

More polished but google is now set on taking over the universe, so they will probably gobble up stellarium.

http://www.googleskydownload.com