I use a Netgear router, and with all 4 ports wired up, I can still use my laptop wirelessly.
Heh, out of 5 things on my router, I own 4 of them so I usually only have 1 other person on at a time, and I dont notice any difference really. My connection seems to be just as fast if im out on my deck, or right beside the router. I love the wireless router I got, makes life alot easier.