1. The King Of Fighters
I love the concept of playing different characters in a single fight. I was a lot of fun in 1994 and it´s still fun today. I love the characters. The only thing that pisses me off in the series are the cheap bosses, but I kept loving that series like no other. I played most installments on arcade and some later installments on my nephew´s PS2.
2. Shin Megami Tensei.
Actually, I just recently discovered that series because some years ago, I had only Nintendo consoles and I wasn´t a big fan of portable gaming (gaming is very expensive in my country and at that time I couldn´t afford to buy and follow more than one console). I got a 3ds in 2011 and after playing Devil Survivor Overclocked, I just couldn´t get enough. I bought every Shin Megami Tensei game launched since then and now I´m looking for older games in emulators. I´bought a PS4 so I can play Persona 5 when it launches. I also bought Tokyo Mirage Sessions for WiiU
3. The Legend of Zelda.
Played it since teenager, since the first NES game, with my older brother. I´ve not played all main games in the franchise but I love it anyway. No fantasy game caught my imagination as strong as Zelda series did. And we still play Zelda together after so many years.
4. Professor Layton
Again, a series that I only discovered recently. Love the characters, the stories, the concept and those puzzles are a lot of fun to solve. And that Layton vs Ace Attorney crossover is amazing.
Other series that I love but not as strongly as the previous four: Animal Crossing, Street Fighter, Mario Kart, Virtua Tennis, Resident Evil, Just Dance (best party game ever!)