There has been a lot of debate about deleted posts over the years. The classic example is the old discussion about handling old popular posts, upon which consensus has never been reached and the opinion of the majority has varied over time (deletion is currently favoured). More recent is Pekka's request that a meta thread be undeleted and the related discussion about the appropriateness of deleting such meta posts (this suggestion wouldn't resolve that situation, but it would improve it).
Much unnecessary conflict comes from the fact that deletion is not the optimal solution in most cases, but the Stack Exchange software doesn't provide a better alternative.
How often is it actually necessary that content be made entirely inaccessible to most people? Occasionally there will be an genuine need for deletion, such as when copyrighted content is posted illegally. However in most cases posts are just deleted not because they're inherently harmful, but just because it's either useless or misrepresentative of the site, and someone wants to get it out of the way.
We're currently forced to choose between deletion, which wipes content of the site and breaks links, and locking, which preserves broken windows in question listings and inappropriate reputation gains.
I request the alternative of delisting questions. Delisted questions would behave like locked-and-deleted questions except that they would be visible to anybody with a direct link. A background color and notice would make it clear that they're not meant to represent the site. If you wanted to absolutely minimize their impact they could even be
noindexed and removed from search2.
This might seem like a lot of trouble and complexity1 but, as was discussed in podcast 27, it's important to preserve the web when possible. Stack Overflow shouldn't be breaking links and taking content off the web without a good reason.
(Partially a repost of my answer here.)
1 If deletion were modified, instead of replaced then it wouldn't really increase complexity, but I thought people might prefer this.
isdelisted option would be nice.