You can use nessus from
here. It's a great program... they update the plugins often to keep up with current vulnerabilites, and you can use it from the cmd line, gui, or remotely if you enable nessusd. You can even setup nessusd on a remote *nix box and use the win32 client to control it

... oh, and it incorporates scanners like Nmap, as well as many others.

If you're looking for something like x-scan, this is definetely the way to go. It creates detailed reports which i find to be much better than x-scan's reports.