I would say that as a kid I used be right on top of the topic, but sadly I just never did much with it.
Your suggestion to pick up Beard's book, at this point in my life, is probably a good one. A few years ago I downloaded Mike Duncan's History of Rome podcasts and I was surprised by how much I had forgotten. And since I have come to learn that I don't seem to retain anything from podcasts, it is probably a good idea to read a good survey book.
The reason I was interested by your comment on Gibbon is that even as a kid I never really saw that Rome had ever fallen - but how much currency does a kid have?
Anyway, about maybe 10 years ago or so, I came across passing references to the idea that Rome perhaps hadn't "fallen" but rather had transformed itself in the church. So obviously, any reframing of Gibbon is of some interest to me.
Duncan's
The Storm Before the Storm was surprisingly good. I expected it to be "History Lite" but it was well done. Beard's
SPQR is fantastic as it will remind you of what you have forgotten and certainly teach you things you did not know. It provides a wonderful foundation for Rome's history as an entity. From there, you can branch off into many different works on many different topics. I am quite interested in tactics, so I have spent a lot of time reading about that part of Rome's history.
So Gibbon is a staple in Roman historiography. It is usually the first one, two, or three books an ancient history major reads about Rome. It was really the first comprehensive history of the entire history of Rome. This is what makes so incredibly important. However, as a scholar, one must be weary of using his thesis as fact. That is because he wrote it with a specific purpose, to counter the Enlightenment's thinkers on the matter of faith. He essentially blames the fall of Rome on their loss of morality and faith. In many ways, he is predicting, like John the Revelator, what will ultimately happen to Europe (specifically London and Paris). This is why I claimed it to be allegorical. It comes off as a historical claim, but it is in fact a treatise on keeping faith. This is similar to most of Procopius's work during the reign of Justinian (we can save this for a later time perhaps).
I am not sure that I would agree with Roman Catholicism and Christianity taking the place of the Roman Empire. I can say that up until the Great Schism (and perhaps until the Fourth Crusade), that was likely the idea in the eyes of the clergy. I have written about Christendom (idea of a Christian empire) in the past and have theorized that the Crusades were a part of that idea as were Spain's explorations. Here is a paragraph from that essay:
"The Crusades represent yet another major turning point in European history, especially when the idea of Europe is considered. The Crusades was a calling to all of Christendom to unite and fight under the flag of faith to defeat the Muslims who occupied the Holy Land. This was an important goal for several reasons. One of those reasons being the thought that the Roman Catholic Church was the continuation of the Roman Empire (footnote here: Housley, "Crusades and Islam"). The Roman Empire, famously, once occupied this territory and as it was this empire that spread Christianity throughout Europe. Another reason was much more fundamental, as Jerusalem represented the place of death of Jesus Christ . His blood was shed on the very ground just outside of the city. To think that the Muslim infidels now ruled this land was tormenting to the pope and ecclesiastics. Yet another possible purpose of the First Crusade was an attempt at pushing the issue of secularists, who were in debate with ecclesiastics, to the side by uniting in conflict against Islam. When Pope Urban II called for the ‘Holy War’ against the Islamic caliphates, many kingdoms obliged and set sail to the Levant and Anatolia. Although the soldiers, barons, dukes, and kings who fought in the First Crusade (1095-1099) were of different backgrounds, cultures, languages, etc., they united under the church and under the faith. "
This comes from an essay regarding the idea of Europe. That idea was born of Catholicism. While an entity such as the Roman Empire did not reign in Europe, a very real entity did in the Medieval World: the Catholic Church. Emperors and Kings kissed the ring of the Pope and constantly vied for Papal favor against one another. Completely disregarding a "fall" of Rome is incorrect and bad scholarship, I feel. There was a clear fall of Rome and although you may argue it only lasted a couple of hundred years or so, there definitely was a fall. The result was a cultured Germanic people that spread that culture throughout Europe. Once they, too, were transformed into Christians, Europe never looked the same.