WordPress lets you change the way your pages appear in the address bar in many different ways using mod_rewrite. Using the preset tags you can get all sorts of combinations, turning ugly URL’s like http://example.com/?p=N into search engine (and user) friendly ones such as: http://example.com/year/month/day/post-name

(note: you can find this feature from Admin CP >> Options >> Permalinks)

John Chow uses simply

/%postname%/

While Darren Rowse at Problogger.net uses

/archives/%year%/%monthnum%/%day%/%postname%/

These guys are two of the top Bloggers around so it’s strange they use wildly different methods yet are both big money makers. I personally use a method similar to Darren but I exclude ‘archives’ as there is no huge benefit to it as far as I am aware.

I would recommend that whichever method you choose to go with, you include %postname%, probably the most useful of the tags for SEO. A search engine will see the page title with the keywords you want to be found by and give you a few more brownie points for helping visitors.