I have only the MSN Windows security blanket that comes with Win 7. Do I need other, more, security besides that?
Thanks.

In my opinion, yes. Consider placing a NATing hardware router w/firewall between your computer and the Internet gateway device (cable modem, DSL modem, etc) on your network. Another brand of software security suite on the computer itself wouldn't hurt either. Also, patch the computer every month automatically or manually via Windows Update. Finally, think before you click on any email links.