I appreciate everyone that corrected me but all the arguing in the world doesn't change the fact that the iPhone transfers data 8 times faster over USB than wifi; tethered, ssh, sftp, syncing, ... you name it.
I live on a boat with an iPhone and a laptop. My iPhone is my ONLY internet connection. I've tethered it with the "carrier file hack", iPhoneModem, PDANet and MyWi. MyWi is the hands-down winner - plus it allows you to tether via wifi, bluetooth or USB. The USB tether blows the socks off of all the others. Speed tests are comparable to DSL.
I am on AT&T with a 16 GB 3G off the coast of Los Angeles, CA.