[whpalmer4]

You've got a lot of on hold projects, but how often do you change a project between on hold and active? I think that is perhaps the most crucial variable in deciding whether or not you can shuffle the on hold projects off into cold storage, with the ease of determining where they go when active being a close second. Unless changing between active and on hold is very infrequent, I think it makes more sense to leave the projects in place and simply adjust your views to hide the inactive projects. Similarly, if it is difficult to quickly return an on hold project to its proper place when it becomes active, that also argues for leaving them in place. You don't want to spend any more time than absolutely necessary fiddling around with OmniFocus — spend the time knocking off some tasks!

If you really want to segregate on hold projects, perhaps having an on hold folder in each major folder would ease the job of putting a newly active project back in the right spot. Alternatively, just move all of the on hold projects to the end of the group of projects in a given folder, which you can do easily by selecting the projects in the sidebar and using Edit->Sort->By Status (active projects will move to the top of the selection, on hold to the bottom). Stuff you are certain you won't work on in the foreseeable future you could shuffle off to the Someday/Maybe store.