Yeah, my router for my wireless laptop does a, b, and g. I just use a, though, because the signal is strong enough to go through my whole house (and likely out onto my back porch, though I haven't tried that- too cold) and not too many people have 802.11a cards. I use WEP and MAC address filtering, and I'll be going to static IP when I get time to fool with it. It's not likely someone is going to get on my system (would have to guess my MAC address (only one specific address allowed), my IP network range, and then the WEP key.)
