Erase and rewind: 4 ways to "delete"

Thinking about models for deleting files or messages...
I can think of 4, but which is best?

1. Delete (as in now and forever) e.g. Visio. It doesn't matter how long you've been working on that prototype, it can still be gone in less than a second.

   And why on earth would "Rename", "Insert page" and "Delete" be so close together?! :o
   
   

   1st lesson to remember: regularly save file under different names.

   2nd lesson: design products which avoid mixing up innocuous actions with potentially project/career-destroying ones.

   This would be a good point to refer back to one of Jakob Nielsen's original 10 heuristics:

   "Error prevention

   Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action."

2. Delete --> You sure? Yes / No e.g. Twitter.

   
   It's interesting to note that Twitter really emphasizes the fact that there is no "undo".

   I guess google applications have had a big impact on user behaviour and expectations...

   - Though shouldn't it be "no undoing"?!




3. Delete (move to recycling bin) e.g. Yahoo mail or Windows.
   
   

   Ok for medium - advanced users, and for those who have had a heart attack over some super-important file "disappearing".

   However, it's a pain if you're deleting a lot of files and it's not immune to mistakes, but the "Are you sure?" dialogue box is still a good safeguard.

BUT it's not that intuitive as a lot of users don't know they have a recycling bin!



4. Delete + Undo (e.g. Gmail) Probably still the safest method AND you get a confirmation message. Though if you really want to delete something, will it even let you?!
   

Know of any others?