explorador - 6:35 pm on Feb 3, 2012 (gmt 0)
I used to have left aligned websites, but the screen size at the time didn't matter, it fitted well. Then as screen size and resolution increased, it looked ugly.... (you can do wonders with backgrounds and liquid layouts).
Now, due to the new standards, remember that you are centered regarding your monitor, so avoid making your users look at the left or right side of the screen when the most natural position is facing forward, to the center of the screen...
just my opinion... but I never measured the diffs regarding that change, but if it serves you well, earnings have been climbing, only one site died but it was panda related, the rest continue to slowly climb