I'm a fan of wireless. When people bring over laptops, its a lot more convenient to have them connect to my 802.11g router wirelessly than stringing ethernet across my room. I have cat5 cables wired through my walls to much of my house, so the desktops are all wired. I use wireless for my Pocket PC as well.
Anyway, my wireless access is in no way vulnerable. I use 128bit encryption as well as MAC Address filtering. It would take a LOT of time and effort to break in. Speed is rarely a problem. My internet connection never exceeds 1.5mbps, far short of 54, 22, or 11 mbps, so the wireless connection is not a bottleneck. It is only a problem when transferring large numbers of large files, in which case, I wire the two computers together with a 100mbit connection.