pshea - 7:02 pm on Sep 10, 2007 (gmt 0)
I spent a lot of time over the past 6 mos cleaning up my code so that each page validates. While I don't think there's any benefit to Google if you skip an Alt tag here and there, there is the idea that this could matter in the future. As Google marches along it increases the characteristics that are important to the algo. By doing this housekeeping, you are ready if this happens.