Need expert opinions

[rcmedia2004]

Hi,

I'm buidling a new site for someone and was wondering which site hierarchy and file naming system to go with that would help search engine rankings.
In our business, the file names seem to have a huge impact on the rankings.
A lot of our competitior's don't use sub-folders for inner pages (*i.e. all of their site pages/html files are in the parent /root directory.)..but many of them use our top keywords in their actual html file names
example: www.yoursite.com/keyword1-keyword2.html

I wanted to do something like .../keyword1-keyword2/keyword1-keyword2-keyword-3.html
using keyword named sub-folders because this is a huge e-commerce site and it would be a nightmare to admin with all the files in the root directory.

Any opinions or advice on which naming shceme to use would be greatly appreciated.

PS - I did an experiment a month or 2 back where we added a new line of products for a client to their e-commerce site. I created a keyword specific named sub-folder and then used the exact same keyword specifics for the html file name..so it ended up looking like this..>>>

http://www.oursite.com/keyword1-keyw...-keyword3.html

Within 2 months at the most we are top 10 in both Google and Yahoo for that particular keyword.