Yubikey nano

Yubico have released a new kind of Yubikey hardware token, the nano. This one is basically a plug for a USB port, you leave it in the computer and it has a small ridge you can touch to generate the one time password.

It also supports continuous challenge/response authentication, ie a site can ping the key to demand reauthentication whenever it wants.

They're a bit more expensive though, $40.

They look very interesting. I'm thinking of getting a few of these to the impresscms site administrators, to add another layer of security.