Alright, i'll put it out there and let those that wish to beat on this post.. :D
For a street car...
Shift at the lowest RPM that runs the best ET. Run the same at 5500 as 5800? Shift at 5500
Run the best highway gear that doesn't lower the ET. IF 3.55's run the same ET as 3.91's, run the 3.55's.
Total timing - run the least WITHOUT giving up any ET. If it runs the same at 34 as 36, run 34.
Keep the car running it's best ET, that is most important. But do it by staying at the lower end of all spectrums. Live Long on the street in a car you'll enjoy, while being as fast as the build allows. :)