If you look at the metastudies on this topic, you will find that the difference in averages are 4 to 6 IQ points, depending on which metastudy you read.
Since the average IQ is by definition 100 points, we're talking about a difference in averages of only 4% to 6%. Yes, atheists are smarter. Yes, the difference is statistically significant, but in practical terms, it's really too small to care about.
Frankly, from the histograms I've seen, we have a group at the top of the intelligence curve that is probably throwing the average off. Everyone outside the super-genius segment of the histogram is probably not appreciably different from their theist counterparts.
Further, as more and more theists become atheist, the difference in average IQ is likely to shrink even further.
Stop gloating and beating your chests. Becoming an atheist didn't make any of us any smarter.