there are many good shop where you could spend some good time. here you a list of some pretty famous magic stores:
galactus, via alessandro malladra here you can actualy play all the formats and buy everything
strategia e tattica 2, via massaciuccoli, here is mostly draft, standard, edh and extended. they even got a good card pool that you could buy.
fucina del drago, via arnaldo vassallo mostly standard and draft, with a good card pool
games accademy roma, via gualdo tadino edh, legacy, standard, and booster draft. a good shop with a good card pool
maremoto, via duilio another rly good store in the center of rome
strategia e tattica 1, via cavour one of the oldest places where to buy magic in rome
there are many more that I don't know about, but trust me Rome is pretty fullfilled with magic store!

Referenze: t4v, guido80, panda94, holtzman Engine