JSPs that otherwise appear to work do not expand JSP expressions and instead have include the actual expression in the generated HTML.
This is caused when using JSP2.0 against a 2.5 web.xml. Jasper 2.0 silently fails to evaluate the expression - but most other JSP functions appear to work.
The solution is to either use a 2.4 web.xml format or upgrade to use jasper 2.1 (simply running java5 should be sufficient for jetty to automatically select jasper 2.1 if the jars are present).