Breakpoint, an earnersforum member, calculated the AOL data from August and showed the difference in clickthrough rates for the top 10 search results. How important is the #1 spot? Pretty darn important. Here are the figures:

Total Searches:9,038,794
Total Clicks: 4,926,623

Click Rank1: 2,075,765
Click Rank2: 586,100 = 3.5x less
Click Rank3: 418,643 = 4.9x less
Click Rank4: 298,532 = 6.9x less
Click Rank5: 242,169 = 8.5x less
Click Rank6: 199,541 = 10.4x less
Click Rank7: 168,080 = 12.3x less
Click Rank8: 148,489 = 14.0x less
Click Rank9: 140,356 = 14.8x less
Click Rank10: 147,551 = 14.1x less

Interestingly, position 10 does slightly better than position 9, which is what I would have assumed, since it will be the last place for the eye to land if not satisfied with the previous results.