I suddenly realized that this is actually a coherent question and googled it. 125 billion. This bothers me! Not that the number is too small or too large but that it is a finite number. I guess I've known since I was a kid that if you keep going far enough in a straight line through space you end up at the place where you started, but somehow this hadn't really sinked in and I still thought 'universe' ought to mean 'everything' and thus 'infinite'. 125??
Edit: on second thought, this means that there are as many neurons in your brain as there are galaxies in the universe. Take that atheism!
Random rant brought on by cosmologist Sir Martin Reeves speaking at TED (18min):