Reposted from 2010 to add this new information:
There are a dizzying 2 trillion galaxies in the universe, up to 20 times more than previously thought, astronomers reported on Thursday. The surprising finding, based on 3D modeling of images collected over 20 years by the Hubble Space Telescope, was published in the Astronomical Journal...And each of those galaxies can have a hundred billions stars... But, according the Sky and Telescope, "we do not "also have to update the number of stars in the observable universe, which now numbers around 700 sextillion."
Using deep space images from Hubble, Conselice and his team painstakingly converted them into 3D to measure the number of galaxies at different times in the history of the universe.
Lots of relevant links in this Reddit thread.