Safari:lock cookies or cache from deletion??

[starcrossed]

I was wondering if anyone knew of a good way to lock cookies and cache from certain websites, to prevent them from being deleted. The reason I ask this is because I enjoy how some websites, message boards, etc, remember the last time you visited and tell you what is new that you haven't read and so forth, or remember user names and all to make it easier for you every time you revisit. But I have a habit of reseting Safari right before I close the program to get rid of unwanted cookies and cache files, but lose the ones I want in the process. I know I could go into the prefs and delete the ones I don't want manually, but that can be time consuming. So hopefully someone will be able to provide me with some good advice to help me out, thanks.