I think the R2D2 robot is one of the most popular movie robot of all time. You will find it in every "best movie robots" posts all over the net. But I think R2D2 would not be that popular without its friend C3PO. Have you seen the new trilogy? Separated, the two droids lost most of their funny side. So what is it that make them so popular? How can a speechless robot be so useful? And how can you get your own personal robot like this one?
The useful versus the useless, the talkative versus the speechless. These two space robots couldn't be further apart. But together they can achieve miracles (well, especially the R2D2 robot, actually). They are specialized to the extreme, one as a toolbox, the other as a chatterbox.
In the movies, R2D2 often comes as the last resort solution for deadly situations (like when Luke and his friends are being crushed by the dumpsters of the Death Star). On the other hand, C3PO is here to break the tension and create humor at the most unexpected moments (remember the first kiss of Han and the Princess?).
But together, they make the most awesome couple. The little cute R2D2 robot does whatever it wants while the golden humanoid robot does the chatter for two (especially the ranting). The astromech is necessary to make the action go on, while the protocol robot is necessary to clarify the situation for the public.
In Star Wars I, C3PO's role was given to Jar Jar Binks, who is a little more dynamic. The next two episodes are just not funny. So only R2D2 was kept.
No. Really. It would be easier to say what it cannot do: speaking and climbing stairs (note that stairs do not exist in Star Wars...).
On the other side, the Astromech can hack the Death Star, projects holograms, electroshock all kinds of annoying aliens, locate people or signals, serve as a fire extinguisher, or even as a butler in parties. It can also repair space ships, and is one of the only Star Wars robots that can be used in outer space. Note that its inability to climb non-existent stairs is compensated by its rocket thrusters.
Another very interesting skill of the duo R2D2 C3PO is their ability to avoid being hit in the middle of the battles. They are like ghosts on the battlefield that no blaster can aim at.
A few fans pointed out that some of its gadgets could not fit in its body (like long arms used to grab objects or connect to computers), left alone all of them together. So my guess is that it can change its current configuration before going to a new adventure. But I may be wrong...
I would really love to get an R2D2 butler robot like in The Return of The Jedi. It would go from my kitchen to the living room to bring plates or drinks to my guests, and then bring back empty plates to the kitchen. Actually, a robot called Luna was demonstrated in 2011 and that may soon do just that. I also talk about it in Future of Robots.
But if you really want your own, you can get a small Star Wars Interactive R2D2 for less than 200 USD. It is small but can do some cool stuff for a toy. It won't carry your plates from room to room though.
So if you want a really cool robot, the best way is to build it by yourself. You are not alone, a lot of crazy Star Wars fans made some very accurate reproductions of the R2D2 robot or its Astromechs friends. And there is a website that will definitely help you: R2D2 robot site. Actually, this website has EVERYTHING you need to know about R2D2 robots! Every gadget it has ever used, every different series presented during the movies or the comics... I send you to the FAQ because there you get all the most important information (like what budget do you need? where to find parts? and so on).