micbr Another issue is if a user deletes their account, is the username then automatically released for another user to claim? Because this could be a very bad thing. Essentially someone could take the deleted users identity and use it to gain the trust of other forum users who perhaps knew the now deleted member, or post from their name to slander or ridicule them.
Or conversely, a new member could unknowingly take the username of a deleted member who acted like a perfect ass, and end up being subjected to ridicule (or worse) simply because he/she is using the same name.
Auk I imagine Account ID combined with previous accounts appearing as [deleted] can dispel this kind of issue.
Since that would allow the reuse of the name, the issue would remain. The only way to dispel any issues resulting from the reuse of usernames is to prevent the reuse of usernames. Leaving the username in place is the easiest way to accomplish that ... and as I explained above, it also avoids other sorts of confusion.
I don't see username availability as a big issue. On the very rare occasion when a user absolutely needs to use a name attached to a deleted account, it can be handled by petitioning an admin for assistance.
I think the route suggested by Toby is the best way to do it.