I think a lot of people have it wrong when feeling frustrated that the MacBook only has 1 USB port. The whole point of this machine is to push for the advancement of wireless technologies. It will force users to find other methods of performing certain tasks where they would use a conventional USB connector/adapter. As far as I am concerned, that USB port is just for charging it.
It has AirDrop for transferring files, Bluetooth for files and wireless headphones and accessories, Wi-Fi for connecting to the internet, AirPlay for wireless presentations on a large screen.
I'm not saying that these wireless technologies are great yet, they still need a lot of work and need to be more open, but the MacBook is pushing for an era where these technologies will be really great. Hopefully competitors will try to copy this approach and wireless technologies will really move forward.
If you really want more USB ports, get a MacBook Pro.