If you are talking about PS4 Exclusives, and allow remasters, this would be my list:

The Last of os Remastered
Nathan Drake Collection
Bloodborne
Until Dawn
Infamous: Second Son

With No remasters:

Bloodborne
Until Dawn
Infamous: Second Son
Uncharted 4
Ratchet and Clank

All titles, not just Exclusives:

The last of us Remastered
The Witcher 3
Rise of the Tomb Raider
Assassins Creed Syndicate
Uncharted Collection

In no particular order:

1. Bloodborne (currently playing)
2. Uncharted 4
3. Beyond: Two souls (in the gen of remasters there needs to be at least one in each list;p)
4. Final Fantasy XIV
5. Dragon Quest Heroes

Says the man that hasn't played it.

I was going to say this. Pervy Sensei, you need to get on it. we await your arrival. 

Bloodborne
Uncharted 4
The Witcher 3
Metal Gear Solid V
Infamous Second Son

1. Dark Souls 3

2. Bloodborne

3. Uncharted 4

4. Infamous SS

5. MGSV < I'm very disappointed in this one, good game but nothing special. It is only on my list because I haven't played many games. I'm very certain that FFXV and The Last Guardian will take a special place in my heart soon.

By my count, there are 14 people using their PS4s incorrectly.

1. Bloodborne
2. Salt & Sanctuary
3. Dark Souls 3
4. inFAMOUS: Second Son
5. Dark Souls 2: Scholar of the First Sin

Counting only true exclusives:

1. Bloodborne
2. inFAMOUS: Second Son
3. inFAMOUS: First Light
4. Uncharted 4
5. Until Dawn

1. Bloodborne
2. Dark Souls 3
3. Uncharted 4
4. Until Dawn + Rush of Blood
5. Guitar Hero TV

Just created a new account because it's impossible to reset password... no e-mail received from VGC, even in spam folder (it doesn't work??)

1. Uncharted 4
2. Metal Gear Solid 5
3. Digimon Story Cyber Sleuth
4. The Last of Us & GTA 5
5. Bloodborne

But Final Fantasy 15, PERSONA 5 !!!, Yakuza Zero !!! , Detroit Become Human and Horizon Zero Dawn are coming !

PS: Question @ Metal Gear Solid Fans

http://gamrconnect.vgchartz.com/thread.php?id=222783

1. The Last of Us Remastered
2. Uncharted 4 : A Thiefs End
3. Until Dawn
4. Batman Arkham VR
5. Driveclub VR

Honestly, five is impossible. Just like asking the five best games of all time, you can't do it without leaving out amazing titles. In reality the library of games on PS4 is incredibly deep, and as much as I believe in this list, it absolutely pains me to have to narrow it to five. So much great content on this device.