i think most powerbooks sold bye apple now come airport ready
but getting to ur question, you dont need to get the airport base station itself, any b or g network will work with the airport extreme cards and any b station will work with the original airport card. that being said, i would go for linksys or netgear base stations if you arent getting an apple
the apple basestation is the simplest to set up and like the previous poster mentioned can do wireless usb printer sharing