What Fyron says about USB speed is mostly true, but isn't really so much of an issue when looking at a choice for a DSL modem. Ethernet is much faster, but both of them are faster then your DSL anyway. Ethernet isn't going to suck data through your phone lines any quicker. You would notice a difference between USB and Ethernet if you were comparing local area networks running flat out. But nobody hooks up LAN's using USB.
That being said, I can't really think of a good reason to go with USB over Ethernet, unless you just really are opposed to getting an ethernet card for your pc and have a USB port sitting there doing nothing. USB is slightly easier to setup, but today's ethernet isn't that hard either. Most of the cards are plug and play, and the software that loads the drivers is pretty much idiot proof. (Not that you'd need that Krsqk.
) And Ehternet does give you more flexibility down the road if you decide to setup more then one computer on your home network to share that DSL line.
[ June 02, 2004, 19:40: Message edited by: geoschmo ]