ZigBee will be in your home sooner rather than later.
ZigBee is a set of application and security standards that build on the physical and MAC layers defined in IEEE 802.15.4 standard. Its main application is for monitoring and control environments. This contrasts with Bluetooth, which is really a cable replacement technology, and WiFi which is a broadband mobility technology.
Zigbee is characterized by
1. being very memory/processor unintensive (requiring an order of magnitude less memory to run compared to Bluetooth),
2. having very low duty cycle (and thus very long primary battery life measured in years),
3. supporting static and dynamic star and mesh networking across thousands of nodes, and
4. delivering tens of Kbit/s over a range of 70 meters.
The first security system earned Zigbee Certified Product status back in February. The core of the system is The Hub that plugs into your power and broadband modem and monitors all the other sensors in your home: alarm detectors, motion sensors, and (panic) Buttons. As a customer, you get a Keyfob (much like your car remote) and website access letting you monitor and manage your home from anywhere.
There are many products today, not just in home management, but also in energy efficiency management, and in building and industrial automation.
I can see Zigbee applications feeding into wired and wireless in-building and public network environments, and providing users wherever they are or however they are connected with a window into these applications (e.g. as in the home management security system described above).