What's better now? A super-short URL structure or a slightly longer, more descriptive URL structure?

[IDWholesaler]

This post is deleted!

[Francisco_Meza]

I would lean toward www.mysite.com/product-category/12345.html . However, if you can structure your URLs like: www.mysite.com/catergory/keyword.html  After that you may want to run it through on page report card.

Small Addition:

/category/subcategory/product/  OR /category/subcategory/productkeyword/

[KeriMorgret]

Don't forget about analytics. It can be helpful to have some directory structure so you can look at various aspects of the site in aggregate in your favorite analytics package. If you have categories of /golf-clubs/, /golf-shoes/, and /golf-towels/, with having them in a directory structure you can look in aggregate about how all of the pages about golf clubs are doing on your site. Lunametrics has a post at http://www.lunametrics.com/blog/2010/09/22/designing-google-analytics-friendly-site/ with more ideas.

[seowebjunction]

I agree with Keri here. If you want to be able to produce detailed reports, consider doing it the way described in the Lunametrics blog.