Affinity is just a good name and a great word...it's the heritage of the deck. Admittedly we're not shifting skullclamp around with disciple of the vault (shocker - the main engine of the broken deck wasn't 'affinity' per say) but Cranial Plating still feels pretty unfair at times.
Robots and Artifact Aggro before it (seriously yuck) are just dull names.
Regardless though, it should be mandatory to crack lines like 'autobots, roll out' every time you swing in with a group of the loveable little 'droids. Unless someone tries to get Autobots to be the next name. Or Androids. Leave it be.
Robots sounds cooler. It sounds a lot more manly than "affinity." Metalcraft is... boring. It sounds like a new popular MMORPG.
The only problem with using the term "robots" is that, especially in pauper, there aren't too many robots in my deck. I think I'm only using Frogmite and Myr Enfoforcer at the moment.
But it doesn't sound cool! It sounds meh.
In your head though, just say "Affinity." It comes out in Tezzeret's voice doesn't it? Deep and manly, but a little raspy, a voice that causes fear in the hearts of the opposition.
Now say "Robots." It sounded like a small child looking through some Robot toys at Wal-Mart didn't it? A voice that does not inspire fear, but relief in the hearts of those once fear stricken by the thought of the deck!
currently my deck has only one affinity card, two metalcraft cards, about 50+ artifacts ....
i either just say Tempered Steel ... or 'this is my artifact deck' ... eh ... most in my area here artifacts and say affinity though ... or ask if it has the Urza lands in it ... so they can call it Tron ...
though i guess since a fair amount of my wins come from inkmoth nexus + tempered steel + Cranial Plating .. i should just call it my Infect deck ...
To me the argument about there being a right name misses the nature of changes in language in dialect and divergences in decks.
Currently there's two directions that the deck is diverging into, ish. One is just as fast as possible. It's the true heir to the deck being a combo deck that wins in the red zone. That deck is affinity. There's also the trend toward slower, more burly decks. Those are Robots. Are you trying to give the other guy a save or die in terms of hitting Pyroclasm are are you trying to be a bit slower but a bit more obscene in terms of synergy, etc.? If so, you're clearly punching the guy to death with... Robots.