I have received my Yubikey 2.0 from Yubico and it is nice.
The biggest new feature is it has two internal configurations. Each can be programs with different functions. With Version 1 of the Yubikey you could program it to be a static password or reprogram it with your own AES-128 key. The static password is nice but much less secure and if you update the AES key you can't use it with Yubico's authintication server any longer. (This has changed.) I wanted to use my Yubikey as a one time password (OTP), not a static password, so I never reprogramed it.
With the new Yubikey 2.0 you can have the best of both worlds. I can now tap my Yubikey and it will give me a OTP or I can hold the button for 2.5 seconds and it will spit out a 64 char password. The password is good for things like TrueCrypt passwords and encrypted hard disk passwords.
– functions like CapsLock doubleclicking, auto-URL navigation are gone.
– It can not be programmed unless you have obtained its AES key – but yubico shiped all "developer's keys" without the protection set.
– It deactivates itself for some time if a failed programming attempt is detected
– can be ordered in various colours (Black and White for now)
– supports a pin: after inserting the key, you need to type a 6 digit [0-9] pin on your key board to activate it (it will blink to indicate success)
You can get your own Yubikey here