I must say that despite yearning for a delete button (and a delete function for that matter) in the beginning, I've just "let go" and gone with the Gmail flow. (Rhymes and all!) I archive almost everything (even cheesy jokes/forwards and newsletters that I know I'll likely never read again). I've left my hierarchical folder habit well and truly behind me and I don't miss it. I used to delete all the time with other email clients to "tidy up" and make important stuff easy to find. No need for that with gmail's labels, stars and search. Now I only delete when I positively want to destroy an email.