As for Halacha in fact the only valid source is the Talmud. But because not everyone has the time it is perfectly fine to go by the Rambam or the Tur Beit Yoseph. The only Achron in Halacha I have much respect for is the Aruch HaShulchan. There are people that go by the Gra in every detail like Rav Zilverman in the Old City. These are all very good approaches. However to know any single halacha properly one needs to know the Talmud from where that halacha comes from.
[What people call halacha nowadays is a joke. They take the majority of the frauds and liars that are as crooked as snakes and go by the majority opinion. That is what they call Halacha.]