I don't understand what's wrong with the account staying up. Remove all non-required information, change the time zone, change your handle, etc. Your posts won't go away, so it won't be a help to you there.I was just looking for how to do this!
I can see how a million deleted accounts might make for some extremely confusing threads if the posters are showing up as "guest" in all of them.
The problem with the account staying up is for people like me who need to stop procrastinating, and so aren't safe around an open account (and who use a browser that won't let them block a website).
Do you mean "I want to delete this account because if I don't, I can't resist posting."?
If there is no direct way to do it, and you are certain that you never want to post here again, go into your profile details and change your password to some random thing that you won't remember. (Pick a phrase you just heard on the TV, or something out of a library book, for instance.) Tell your browser "Never remember this password" (if you have that option.) Voila! You can no longer post, because you can't get in.