DON'T UPDATE TO LION!
I couldn't be more unsatisfied with OS X Lion. First, problems with Safari (and sometimes I got to restart because it has some problem with Youtube), problems with Finder, my network it's completely deconfigured in comparation with my old Snow Leopard, and now the sound has gone with NO reasons. I hear the sound of the volume going up and down, but can't play Youtube and even iTunes! With all the respect, I thought Apple was different from Microsoft, but now that become this big, feels like thinks the same way.
DO NOT UPDATE TO LION! Don't waste your money with a software that have a lot of issues to get fixed.
Mac OS X (10.7)