More and more I am seeing these single ad Adsense banners around and it looks like Google is running tests to improve the performance of them.  Today I have just spotted three variations of the Leaderboard (728 x 90) .

1) Left aligned bold description

2) Left aligned  normal description

3) Centrally aligned normal description, URL on third line

Personally I like them and think version 1 is the most effective. Which do you think works best?