The best one (also best documented one) is http://extremecomponents.org/. I am yet to try it out though but it seems quite flexible and has recently integrated with DWR (http://getahead.ltd.uk/dwr) to provide AJAX support for the data grid. The data grid can include form components. Another good data grid enabling JSP tag library is the display tag library (http://displaytag.sourceforge.net/). I recently also experimented with the live grid example of openrico but due to its insufficient documentation i found it too time consuming to work with (http://openrico.org/rico/livegrid.page). For my project purposes, i settled with the extremecomponents data grid as it seemed atleast as flexible as others and was better documented.