The good thing about today's routers is they work with Apple, Windows, Linux and most hand held devices. The problem with going through floors will usually not be solved by the right router.
There are two brand new iMac's that will be using the wireless router. One on the first floor which is my dad's. He really only goes on the internet for email and we surfing. I am a film student who will be using final cut, photoshop and also play video games on it. the router will be on the first floor and will have to reach down to the basement (1 floor down). I was thinking about just getting the Apple Airport Extreme or The Cisco Valet Plus. Will either of these reach down to my computer and give me the speed I need or will I need a different one? Any recommendations would be very helpful.