Not sure if I'm looking too far ahead, but if there was no SPQR it would be interesting as to which state or kingdom would rise to become a colonial super power in the later eras. Ie. With no Roman influence the UK and possibly even France wouldn't have been innovative and powerful enough to start building colonies around the world. I guess the same could be said for Spain and Portugal? (this is quite a supeficial view point).

I'm guessing that Carthage would have grown significantly as it would have been (majorly) unopposed but who is to say that thier holdings in Iberia would have generated another empire, a Carthago-Iberian one which would rise up and oppose Carthage? Or even another city in Carthage becoming its own empire and fighting Carthage? Much like Macedonia and Southern Hellenes fighting one another, as I believe Macedonian Greeks were southerners that migrated north? (please correct me if I am wrong here).