The real answer to your question is in the "bottom line". By looking over the logs and doing your "homework", you can determine more about which to focus on for the goal (I tend to believe it is still about making money?). I have several clients that rely on G rather extensively because it pays to do so. Others rely quite a bit more on M because that works for them. I believe it has a great deal to do with the niche you are focused on and working through a bit of trial and error. IMHO. There are many great reasons to optimize for both and I do not want anyone to think I'm stating to completely disregard either of the major search engines (heaven's no!). What I'm speaking of is to focus a bit more towards one or more based on specific measurable results as you go along.
Not sure if that is correct anymore or not. Google was, by far, the site that sent me the most traffic. However, Yahoo seemed to kick it into hi gear in support of my site in June, accounting for about half as many hits onto my site as google. IN July, Yahoo climbed to within 10% of Google's totals. For the month of August, Yahoo is close to doubling the traffic it brings me compared to what google brings me, and I have doubled my total traffic already this month compared to what I got in July. Now, I dont know if this is a trend that anyone else is seeing, or if it is simply a result of Yahoo just loving me alot more than G or MSN. I have some pretty good rankings at Google, and havent checked Yahoo lately, guess I should just to see why the numbers look so good from Yahoo lately. anyway, still basically sucking with MSN, but at least I do will with 2 of the 3.