I've had several clients with this issue; they don't want users to have delete permissions, but need to address how users will get rid of documents no longer needed. There are 2 ways to handle that:

1) You can actually give the users 'Delete' rights, but not 'Purge' rights. This will allow users to delete those documents, and they'll go to the Recycle Bin, but the users cannot purge them from the Recycle Bin. In this scenario, you would also turn off the auto-purge on the Recycle Bin, so all "deleted" entries will remain in the Recycle Bin until an Administrator manually purges them (or restores them to their original location if they were wrongfully deleted).

2) For clients that still aren't comfortable with #1, I've created an additional folder in the repository called "z_RecycleBin" or "z_Deleted" (or similar; the leading "z" keeps it at the bottom of the folder tree). Then, users can cut/paste documents they would normally want to delete into that z_RecycleBin folder. This way, they are not actually deleted and sent to the real Recycle Bin, but they are out of the way and no longer muddying up their day-to-day use folders with unnecessary documents. (Repository Admins with 'Delete' privileges can check in on that folder regularly to verify and actually delete those entries, if necessary)