You're quite right about Internet speed (browse, play games, view streaming video, download). The slowest link determines the maximum speed you can reach. And that's that 15 Mbps modem. In practice, you won't even reach that speed.
But you'll note a difference when transferring files between different computers in your home network. Like when you transfer a 4 GB movie from your PC to your home media server. Or when making a backup across the network to your networked file server. Or don't you have such?
My motorola cable modem download speed is 15Mbps, I want to get a wireless router for home. N-routers claim up to >300Mbps, which wireless router should I get and what is the best speed that I can expect?
I thought the wireless speed is limited by the cable modem speed. Is this right?