I've spent a long time with the shiny new Civs like Celts, Ethiopia, and Maya. It wasn't until I started playing a lot of the classic Civs again that I realized how great Stonehenge is, thus my vote is Stonehenge.
10% growth on ToA is OK, but considering you can grab additional growth bonuses through religion (indirectly Stonehenge) you are not completely missing out. And like Mr. Bison points out, ToA is much better later on and you can just grab it then, where as the faith from Stonehenge is much more useful right from the start.
Also, Pyramids are much better in wide, sprawling games which don't seem to get a lot of love around here. The increase on tile improvement stacked with the Liberty policy is awesome when it is key to get a lot of those luxuries, roads, etc. developed ASAP.
Pottery is nearly always my first tech, and if I manage to pop a free writing ruin after, I am often tempted to try the GL gamble.