I've found it useful to set "Highlighting duration" in the options dialog to 20000 ms so that I have time to investigate already-exited processes after the fact. I've noticed that recently exited (red background) processes are treated for column-sorting purposes as though they still used whatever resources they were using on the last update before they exited. It's especially a problem in the otherwise very useful pop-up lists of top offenders in the tray icons for CPU usage, commit charge, etc. Since exited processes are not highlighted there, it's hard to tell which of the listed processes actually contribute to the displayed total.
I think it would make sense to sort resource-use columns of exited processes as though they had a value of zero, while still displaying the value from the last update, if that's not too hard to implement. Alternately, exited processes could be highlighted or greyed out in the pop-up lists.