A unified bar at the top could be absolutely amazing for people that use a lot of google products. My biggest beef with google right now is that even with a unified login, there doesn't seem to be any sort of common interaction between the various google components that I use.
Also, you don't like google instant? I thought that was one of the best features they've implemented in any of their products since... well, for a really long time.
I had this exact problem (multiple gmail/gapps accounts that I'm in all day) and the experience got a lot better a few days ago when this consistently colored bar across the top was rolled out to me.
Also, you don't like google instant? I thought that was one of the best features they've implemented in any of their products since... well, for a really long time.