[curt.clifton]

Are you using flags for anything else? If not, you could flag your low energy actions.

Another option might be to add the word "tired" to the end of the note. Then you could search on "tired" and show those actions. (Searches can be saved in perspectives.)

Once upon a time (last May?), Omni was talking about adding arbitrary meta-data to OF. With that, you could have a meta-data field for energy level and filter on the value in that field. I'm sure arbitrary meta-data is a post 1.0 feature, but I'm looking forward to experimenting with it eventually. Other uses would be recording contacts related to an action or storing data to be used by 3rd party scripts. For example, imagine setting up actions that automatically fire off an email when completed. OmniOutliner has this kind of meta-data, both as visible columns and as hidden meta-data for use by scripts. Kinkless made significant use of this hidden meta-data.