It's really a personal opinion. If I took the time, I could find you discussion saying each choice is better than the other.
Don't think it makes a difference at all... cause the keywords on the site is what makes the difference..
there is not need to change your url to .html.......................because both are same..................just keep concentrate on the keywords in url.............................
because, I just saw someone say google much more prefer the .html pages rather than .php. asp etc dynamic urls. but I saw some website without .html are also have a good postion in google.
there is no different with or with out extension for pages, depending on your optimization for web site.
I find that a silo works better. e.g. http://www.website.com/keyword/ instead of http://www.website.com/keyword.html
The file extension (or lack of one) does NOT affect your rankings. It's all personal preference. Personally, I've grown fond of pages that have NO extension.
What really amazes me is that people make these assumptions with no founded proof. People debate on this issue a lot, but no one can seem to support their claims with hard facts. Using a .html extension is simply customary to what a lot of people are used to seeing. The silo structure is something that I believe came along with blogging platforms and the like. Anyhow, either format, including various other ending extensions are just fine, and don't have a noticeable impact on search engine rankings...at least, that I've ever known.
search indexing technology is not a baby anymore. all extensions are treated with same respect to search engines
I think it's not a big issue. The only difference is you can easily identify a page if it's developed using html or php if it has extension name.