Directory name (with index.htm as default) Vs page name. Which of the following is better for SEO? 1. www [dot] domainname [dot] com/productA-keyword.htm 2. www [dot] domainname [dot] com/productA-keyword - where there is an "index.htm" in productA-keyword directory. - we don't use index.htm in internal URL link I'd like to get some opinions on this.
Definitely use www [dot] domainname [dot] com/productA-keyword. You must also make sure that all your incoming links go to the same dir, and not the index.htm file. Make sure all your INTERNAL links do not go to index.htm as well.
I do not think there would be much difference in SE results. But I would go with the # number two option only because it looks better.
as the keyword in the url is an important factor for ranking and it's even showing in bold so it might increase the CTR of you listings in the SERP's then go with this syntax for the best results: http://www.domain.com/product_keyword/product_keyword.htm or any similar url names just try not make long because search engines loves human readable url's.
I'll go with number 2 option, there is a benefit of using the directory name instead of the page name which is: if you every decide to change the default page name (i.e. from product-page.html to product-page.php) you will NOT lose PR nor links to the old page because in this case, all links and PR will point to the new page automatically.
there is no difference for both of the examples that you mention but i also suggest you to read http://www.mattcutts.com/blog/seo-advice-url-canonicalization/