Well David u see , it actually depends upon , for what purpose do you use your LAN... i mean what are the applications which run in your network.... are you setting it up at home for personal use or commercial use or are you working in an office , and what all are your requirements ?? Broad band will work fine in both cases as its on the external network but your internal network may run a little slow as with 802.1b u will get a maximum throughput of 10Mbps.
Another issue over here is of security ... is your data really really important coz on a wireless network , its relatively much easier to sniff packets. Almost anyone within range with a laptop and Wi-Fi card can do it.
