I think that when planning a site you try to ensure that you use as much keyword rich content as possible throughout the site to satisfy the spiders. Along with creating a keyword infused URL you also need to ensure that your anchors, your general content, your meta descriptions and event the tags for your images are keyword rich. Also, if you are going to create microsites like a blog the name of the blog and the titles of the posts should also be keyword rich. Anyone else care to add to or tweak my advice?

Create content for humans and not spiders. If the content is good and worth reading, the traffic will naturally follow as people naturally link to the content.

Don't keyword stuff your pages by using too many keywords in a manner that reads almost unnatural.

That being said ... keywords don't answer the OP's question of using friendly URLs. IMO, friendly URLs help, yes. I am in favor of keeping query parameters to a bare minimum in URL strings. I am not so sure that keywords within URLs does much help though, as I feel that it seems almost artificial at that point, and doesn't help as much as it used to.

Yep, Search Engine Friendly URLs help in SEO.

By the way, What is that "No advice is stupid" thing?

Also, This is the third forum I think I saw the same post, Are you Copy-pasting the same post on various forums?

Using search engine friendly urls will increase in usability for web users but this could be not single factor for indexing.

it will help of course but remember to create content for the humans just like cscgal said

While I agree with cscgal on some points, I was not suggesting to use too many keywords. It is possible and desirable to write keyword rich content that is attractive to both humans and spiders a like. Do not let the sales force or the techs take too much of an active role in writing the content. But definitely employ a copywriter who knows how to craft content that answers the queries of the site visitor while using the top keywords that you have identified. A solid copywriter knows how to walk the fine line between well-crafted content and keyword happy drek so that the final product is solid.