User friendly URL’s are a personal pet peeve. The last couple consumer focused web applications I’ve written using Struts used a servlet filter to effective rewrite the URL from something like /articles/pets to /do/articles/pets or /articles/pets.do. This same pet peeve kept from me taking any more than a cursory glance at Tapestry, which (at least in the examples I’ve seen) produce some pretty ugly URL strings. Until today that is… Matt Raible pointed out that some guys just converted a 300 page JSP site to Tapestry and the resulting URL’s are pretty nice looking. You can read about how they did it on the Tapestry user list.
Also of note, in Matt’s comments, Dave Keller pointed out an URL rewriting tool on java.net called urlrewrite that looks like it might come in handy sometime.