Lots of changing in the past few years
NBC went from 1st to 3rd/4th
ABC went back up to 2nd and 1st
CBS has reined first for awhile, but it loosing some ground and has been frequently changing place with ABC!
Fox.. is well Fox
Serveral of the new CBS shows are doing well, so I don't see them lossing their dominance this season. NBC needs to find some new hits, and quick. ABC needs to keep doing what they are doing, Lost and Desperate Housewives are huge hits, both new and will be around for several seasons. Their new show COMMANDER IN CHIEF has done great also.
In summary, ABC looks on route to go from bottom contender to top contender. Quite a turn around. CBS needs to seriously watch out, if the CSI craze dies out, they will be in serious trouble.