Introduction
After thinking about my weblog archives, and getting helpful suggestions from friends, and looking at other sites, I've pretty much decided on how my archive URLs will be structured, with one option.
Right now, the only archive URLs that exist look like this:
http://www.keithdevens.com/weblog/3621 for this post
http://www.keithdevens.com/weblog/2003-03-21 for today's posts
Archive URLs
I'm planning to create archive URLs that look like:
http://www.keithdevens.com/weblog/archive/2003/Mar/21
That gives you a day's worth of posts. You can take off each part of the URL and get the month's worth of posts, and then the year's worth of posts. The main archive page gives you a summary view of all years and all categories. However, the old links will continue to work "forever". Keep in mind that this hasn't been implemented yet.
Alternatives
Another option for the archive URL is:
http://www.keithdevens.com/weblog/archive/2003/03/21 (with a numeric month instead of a textual month). I'll make both work in the code (that's easy), but I have to decide what to use by default. I'm leaning towards the textual month. If you have an opinion, let me know.
The capitalization of the month was also a question. I'm going to make it work no matter what case you put in, but I think initial uppercase looks the best (and is more correct according to English anyway).
For now, I'm going to leave the individual post URLs the same. I like how short and simple they are. However, I really like how Simon has his weblog set up, with URLs that look like:
http://simon.incutio.com/archive/2003/03/19/pythonResources
So, over time I may put in short names for posts that are unique within a day and can work like that. Then, posts that don't have titles will still be able to be found by a url like:
http://www.keithdevens.com/weblog/archive/2003/Nov/07/4024
and that will work regardless of whether there is a title such as:
http://www.keithdevens.com/weblog/archive/2003/Nov/07/HappyBirthdayToMe
Categories
Categories are an issue. The problem is that each category is basically like its own weblog. The problem is that you can't just say:
http://www.keithdevens.com/weblog/category/6 (or /06)
and have it dump all the posts ever in that category. So there needs to be some way to organize those posts too. There's no reason I couldn't set up the same type of archive scheme, but that seems to be redundant.
One major consideration is that the posts on a given page (unless it's the "latest" page - i.e. the index page) shouldn't change. So if I were to have /category/6/page2, that would change over time, and that's wrong. I suppose I could set up date ranges, maybe a month at a time. I'll have to think more about this.
Plus, I would like to set up English category names eventually, rather than just numbers, but there's a problem if the category name ever changes. I plan someday to have a "renaming" mechanism in my CMS, so that someday that won't matter and the old URL can continue to point to the correct place, or at least forward to the right place automatically.
Conclusion
I really like how Simon does his site and his archives. He suffers from that "all posts in a category" problem I mentioned. He consistently has the post count within a category, month, etc., which is cool, and I'll copy in one way or another.
I also like how Mark Pilgrim does his site and his archives. He uses a similar scheme to the one Simon uses, so I think they're both onto something. 
I've also looked at sites like CNN, etc. If you have any other sites you'd like to point me to I'd appreciate it, and if you have any comments, let me know. I know this seems like a trivial issue, but it's really not a trivial issue.
I like the textual month. Thanks for keeping individual links as they are.