Depends on how you look at it:

From an internet stand point where you get a new IP every time you sign on, then perhaps that is better than a static. However there are trade offs and I ask "is it really more secure" any vulnerabilites you have will be present wether you have dynamic or static addresses. What little security you gain is making yourself a moving target versus a stationary one. The value in security is slim and the benefits of a static ip in terms of hosting and secure remote access could be essential.

From a net admin standpoint static addresses allow you to disable DHCP which helps prevent unauthorized access to open network (CAT5) ports. With that comes a much higher overhead in IP maintenance so it's only really effective in small networks.