you can have a free roboform addon for firefox,
xmarks just syncs your bookmark list to their server, which means you can logon to the xmarks site from any computer and have your bookmarks, on your pc's at home they can sync between each other so a bookmark you may make on the laptop will show on the desktop when you open your browser,
its not about bookmarks being hacked, a bookmark to a site is only the link to the site so no security issues there,
roboform saves your login information so you can click on a button and it logs you in without the need to type out usernames and passwords ,i too have used roboform for several years and it is excellent,
the free addon for firefox doesnt have all the features of the paid version but for the logon feature you cant go wrong,
i also sync my roboform data to my live mesh folder so it is backed up securely