Robot friend. It's something that has been considered ever since the Čapek brothers first stared throwing around the word robot. Yet there are a few things to consider before picking your robot friend.
First, let's not forget the basic point of view when it comes to technology in general and extrapolate towards a robot. Why did the VHS format overtake the superior Betamax system in the battle for home video systems? Pornography was more available on VHS. What helped fuel growth of the internet in the 1990s? Ever-increasing pornography. Why would a robot friend in human form be any different--would not it be used for the same lascivious purposes? Indeed, this has already been foretold in the... un-landmark episode of Star Trek: The Next Generation entitled "The Naked Now." Made effectively drunk by a virus ripped off from the original Star Trek, Tasha Yar ensnares the android Mr. Data. She inquires if he is fully functional in every way. He replies in the affirmative, and lasciviousness ensues. At any rate, a robot must not be in too familiar a form.
So then we should have a robot which is a bit more mechanical looking. But what about it's internal security? I'm a fan of the film Lost in Space, perhaps because it has the two things that make Heather Graham great (hint: it's not her ability to deliver dialogue and look emotive). At any rate, the robot, called Robot, was an imposing creation that could mind the environmental controls, wheel about on cool treads, shoot a laser beam, AND declare "Danger, Will Robinson!" The downside though was its security. Once reprogrammed by that pesky Dr. Smith, the robot (or Robot, if you prefer the proper noun) attempted to shoot and kill the family. Same thing with Johnny Five from Short Circuit--too much "I want to kill you" and not enough "I want to help you fold laundry." (A brief digression: isn't Short Circuit 2 superior to the original?)
Let us then get the meat and potatoes of it all: our robot friend must be thoughtful, intelligent, human-sounding, not in human form, and non-lethal. I'll add to it that if the robot friend is of appropriate intelligence, there should be some sort of space made to prevent it from interrupting when you're in your bedroom with that hot girl who can fix cars and complain about Michael Bay (see Sam Witwicky vs Optimus Prime). Thus we come to the greatest of all possible robot friends: KITT from Knight Rider. His intelligence and wit will keep one thoroughly occupied and amused--and, for long car rides, he'll both drive and play chess with you. Also, like any good friend, he'll make sure you're safe. Bullets are no problem (tires included), and he comes with wifi, video chat, and a sun roof. KITT is kind and inquisitive, but not in an annoying Mr. Data sort of way; can one imagine asking KITT how long it will take to get to Albuquerque and being told "4 hours, 8 minutes, 15 seconds"? Of course not--he'd say "A little over 4 hours, Matthew."
KITT: the robot I'd recommend.