Security is all up to the user, not the OS. The main differance is that Linux can be easily customized to wall off security issues where Windows based products have a harder time because they have to count on the bug factory in Redmond to produce a proper patch. Another issue is that anyone can easily install win2k, set it up as a webserver, and call it a day. A linux user who does the same knows that he or she must plug some holes before going to bed. So Windows products can be nearly as secure as linux, but there are more security deficiant windows users than linux users.
