A few suggestions I can make on this matter:
1. Whether its Static or DHCP, just remember not to use the default or stand ranges, such as 192.X.X.X make something up.. Using like 10.X.X.X is a good idea, but a pretty common one too.
2. Setting up Static is not a bad idea, but I don't know that its any more "secure" than DHCP, I'm not an expert on that but it sounds like more of an opinion based thing to me. If anything I've found Static to be a pain when it comes to waiting for the communication to wake up.
3. Setting up WEP/WAP is always a good idea, I use it at home and its so good that half the time I can't even get into my own network cause I can't remember the god awful long password.
4. Filtering MAC address also gives you a great boost in security.
You can also concider setting up a limitation on connecdtions. Not sure what type of router you have but i have a crappy cheap Belkin wireless router, and I can set the number of connections, settup wep, configure mac filtering.
doing all three gives you 3 times the security. Its never a bad idea.
to be honest though, i don't believe static is any more secury than DHCP. If your running WEP, and they don't know your code, then they cannot connect regardless as t what they set there IP address to.
I believe there are packet sniffers out there that will pick up the lan address any how, so again WEP Is a good idea. But Mac Filtering is pretty secure as well, unless its possible to change your MAC address, and I don't know that this would help any how.