I think it's still a going to be a while before we see domestic robots in the average home. Todays current experimental robots need the power of several Pentium 4 workstations and recharging every 20 minutes. Better powersources and compact processing power are only a few moore's law leaps away, then
we'll see any explosion of robots in every day life. As well as your laundry, and cooking dinner your homebot will manager your home security, and perhaps be equiped with non-lethal weapons.
The real thing is far off yet. But in the mean time I'd still love to have a bad ass, robocop-animatrix-terminator style robot that could trundle around my home acting as a mobile burgular alarm. It'd have a scary terminator red eye (LED, 5c, radioshack), a aliens-style scanning laser (cannabilised laser pointer and some rotating mirrors), and T-ZERO style tank tracks (pair of car cambelts).
So it looks and prentends like it's some mean as fighting machine with lots of cool brushed aluminum and whirring motors, even does some convincing tricks, but it's really cobbled together from off-the-shelf bits and controlled by a regular home PC. It'll wander about, detect motion, avoid running over the cat, and be wirelessly connected to the net.
Surpose I'm out for the night burgular breaks into my house, he starts rumaging around. The robot is on its random wanderings around my house, microphones detect a noise and via a bluetooth link to my desktop sends a SMS message from the internet to my mobile phone - I'm alerted to something happening. A webcam could send a image to my phone, and I could issue SMS commands. The robot follows wires (saves having complicated navigation software) embeded in the carpet and heads in the direction of the noise. Pausing and scanning each room with a standard infrared motion detector. The burglar is found in the kitchen. A second mechanism with a scanning infrared sensor gets a rough bearing on burglar, the robot turns to face him and (assuming he's not crouching at that momment) THWACK-THWACK he gets hit by a couple of paintball rounds.
A scared sh**less paint covered crook's face can be captured, jpeg'd and sent via email to the police for later detail. Meanwhile I'd have called the cops and would be thanking my semi-effective security bot.