I agree with James on the 'Best posts' pages.
By reporting the posts where a problem has been clearly announced and the answers gives enough informations to let someone looking for help to be autonomous, it may avoid some repetitive questions on the forum. (As I've sometimes done.)

Unfortunately, I think that most of users doesn't take the time to do a search. This is due because of the huge quantity of posts dealing with a subject. It takes a lot of time to read all the posts (sometimes hundreds) and to do the synthesis. I suppose this is why you want to delete some posts.

By sorting the best posts on a topic, the users may obtain more quickly the information.
For example :
a post on SPI, memories, ISP, and so on... will give the informations needed without consulting the whole list of posts.

Thus, you won't have to delete any post. And someone who'd like to consult more posts on the topic may browse if he wants in the archive.

One advantage to keep the old posts even for unsolved questions is that you can still contact the writter to ask him if now he has more informations and if he can share what he has learned....

However, I can feel the work needed to do this synthesis...
But Steve, why don't you ask to some members to help you. I'm sure some members will enjoy to contribute toward this kind of job to improve 8052.com

We could define the categories and assign one category to a member. Its task will to find the best category's posts. Thus the job will be easier for you and will let everyone to participate to the website's life.

Another way to do automatically the job could be to add a 'Vote' button on a thread. Then you'll have to sort the categories by number of votes. Of courses people will vote if the posts have answer to the questions.
The advantage is that the quality of a post will be decided by many persons instead of one.
Sometimes, something which is clear and useful for one person won't be the same for most of the users.

Regards
Stephane