Warning, possible bias ahead.
So there are three anime which I'm sure everyone has at least heard of that tower above all the rest. These are One Piece, Bleach and Naruto, all with at least 300 episodes a pop!
This presents the question for newcomers: Is it worth sitting through all the episodes to catch up, or should I just jump in at the start of the latest arc?
For me, the answer was always obvious. If I were to trully enjoy the series to their fullest, I would have to sit through each arc and come to love the characters. In having done this, or rather, being in the process of doing this, I can say (perhaps with a little bias) that it is really the only way to do it.
I feel that if I hadn't sat through the agonising filler of the Don Kanonji arcs in Bleach, or the Edo side stories in One Piece, I would not have the affection that I have for the cast that I do today. Skipping through is simply not an option!
With that said, the next question most people ask is "Which one should I start with?" and to that, thankfully, the answer is obvious. For recently, a newcomer has arrived in the trinity, with only 150 (give or take) episodes to catch up on, and this is Fairy Tail! So, for any newcomers to the holy trinity, or to anime in general, I reccomend the anime that forms the Holy Quadraplex, Fairy Tail.
From Fairy Tail, depending on whether you like the wackiness and general aloofness of the cast there, you can decide which of the holy trinity to tackle next. If you are, in fact, a fan of the wacky antics, then One Piece is the next logical step. But if you'd prefer a more serious tone and a solid plotline with a potential end in sight, then Bleach is the one for you. If you hate yourself and want to watch a bad show, then I guess you can go Naruto or whatever. But that's on you, bud.