LucidSW - 1:03 am on Feb 8, 2010 (gmt 0)
Conversion rates, unlike click rates, have a lesser correlation to position. However, the top positions generally are better. It will depend on your industry and is something to test. The real number you should look at is the product of CTR and conversion rate which will give you a sale per 10,000 impressions. I've found that it will be best in first position with lower CPS. But your situation might be different and in my experience, unusual, based on dozens of clients in different industries.