Also, applications like media centers will eat up the bandwidth.
Hope this gives you the short answers.
Remember that from machine to machine over wireless would be painful to copy most files at 802.11b speed. This is not used for just the internet.
I am confused as to why companies like dell are selling computers that are 801.11n, when most people's home networks max out at about 1 mbps (for all who don't know, the "N" wireless network can get up to 240 mbps) You can't even buy an interent connection that fast. And most download sites max out at around 1 mbps, even if you are a subscriber. This means that if you had 240 people using a wireless router, they would all have very fast connections. "B" get 11 mbps, which seems fine to me. I say those companies should be working on ways to extend the rangle of the routers, not geting higher and higher speeds that no one will use.