My 8-y-o twins have been studying the Romans at school this term and part of their course involved learning about the Gods and Goddesses, which were all based on the Greek ones. They even had to dress up as a chosen God and give a little speech about themselves. Dayna went as Diana and Aidan was Vulcan. On open day all the parents were greeted by Jupiter at the door. I heard that most of the boys in the class wanted to be Jupiter since he was the 'boss.' 
When I was in school, I remember Roman gods being misrepresented as if Romans and Greeks had all the same gods, but with different names.
I've since learned (and learned more reading up on Athene) that Rome did a "best fit"--example: Minerva and Athena really weren't the same goddess, but the Romans, instead of accepting Athena into their Pantheon as a new god, decided she was similar to Minerva and kept a sort of "population control" on their pantheon. Minerva, originally a Roman agriculture god, came to take on the warrior symbols of Athena.
Several "Greek" gods are Asiatic imports:
1) Apollo (possibly Nordic or Turkic / Trojan)
2) Aphrodite (possibly the Phoenician Astarte, imported from the island of Cyprus)
You see less of this in the Roman Pantheon because the Romans assimilated these figures into Latin gods.
Leading to some weird combinations like:
Odin = Mercury (because they both were patrons of magic)
Thor = Jupiter
Baal = Saturn
The downside is that the Roman historians didn't see point in retaining most of the original names, so like all the mysterious Celtic and Germanic gods have come down to us on paper as like the following:
(a god of the Suebi tribe) => "Suebian Jupiter"
And, finally, a great deal of the gods we think of as "universal to a people" tend to have their origins as the god of a particular tribe or a particular location that then gets rolled into the greater pantheon as those people join the community.
Our learning in school is heavily influenced by our instinct to treat mythology more like a fiction novel with each god being a precise character with a distinct personality who fits into a greater story that has a beginning, a logical progression, and an ending (and with Norse mythology, the compiler Snorri Sturluson attempted just such a thing with his retelling of the myths).
Then, Roman mythology comes along with its hodge-podge of gods and myths and our mind gets blown away trying to relate to it.
-Tim
