Google has been running small checkout icons next to Adwords ads above the fold and large buttons with the sidebar ads for awhile now. They are now placing the large button next to the above the fold ads. I am seeing the large icon on all searches with all browsers so I am not sure if this is a test or something that’s permanent.
I wonder if the Paypal / Yahoo partnership prompted the change. Information arms race anyone? Or maybe it’s in response to dropping CTR rates.