The Bluetooth SIG's board of directors approved 2.1+EDR (Enhanced Data Rate): The revision of the short-range personal area networking standard will reduce power consumption and greatly ease pairing, the association between two Bluetooth devices. The changes can be applied to 2.0+EDR devices via firmware, the Bluetooth SIG told me, but many Bluetooth modules are now in devices that lack firmware upgrade ability. So computers, yes; phones, many; picture frames, perhaps not so much.
Pairing has been dramatically improved by reducing the number of steps and the complexity. For devices that require a passcode entry, version 2.1+EDR requires that one device in the paired set generates a six-digit PIN that is then entered in the other device. And you're done. (Apple created their own version of this years ago, but it worked only when devices were discoverable and paired by Mac OS X to a computer, and it was far less secure than the 2.1+EDR version.)
The PIN is generated, by the way, using an Elliptic Curve Diffie-Hellman algorithm, which avoids man-in-the-middle (MitM) attacks by using an out-of-band method to confirm a key exchange. In this case, the two Bluetooth 2.1+EDR devices generate and exchange their ECDH keys, and then one device generates a six-digit PIN which is part of a hash of the session key being used by the two devices. While an MitM can talk to both parties, they can't know that six-digit PIN.
The improvement in power usage is rather significant: the SIG reports a fivefold improvement in battery life by intermittently connected devices like sensors, and input devices that send very little actual information, like keyboards and mouses.