Title pretty much explains it, which games have you logged the most hours on your PS4, Xbox One, WiiU, 3DS or Vita. Cross gen games count but not if you played them on a last gen system, sorry if you played 100 hours of GTAV on ps3/360, it doesn't count. To keep this reasonable I'm only gonna list the games that I've played at least for 30 hours.

Wii U

1. SSBU  270

2. MK8  195

3. Splatoon  175

4. AC: Black Flag  70

5. SM3DW  67

6. Lego City Undercover  65

7. WWHD  62

8. Batman Armored Edition  47

9. DKTF  41

10. ZombiU  33

3DS

1. Zero Escape: VLR  93

2. Fire Emblem Awakening  70

3. ALBW  69

4. Tales of the Abyss  57

5. SSB  55

6.  Pokémon Y  43

7. Majora's Mask  38

8. OOT  37

Xbox One

1. Halo MCC  176

2. Dragon Age Inquisition  94

3. Shadow of Mordor  65

4. Magic Duels Origins  65

5. ROTR  38

6. Alien Isolation  32

7. Batman: AK  30

Count me down for 516 on Rocket League. Close Second is Borderlands 2 with 60+.

3DS:
1. Pokemon X: 497:46
2. Fire Emblem: Awakening: 234:09
3. Pokemon Omega Ruby: 151:27
4. Mario Kart 7: 71:54
5. Super Smash Bros. for 3DS: 45:22
6. Super Mario 3D Land: 32:26
7. Pokemon Shuffle: 29:43
8. The Legend of Zelda: Tri Force Heroes: 28:49
9. Paper Mario: Sticker Star: 28:03
10. Pokemon Y: 26:31

Wii U
1. Super Smash Bros. Wii U: 95:29
2. Mario Kart 8: 65:19
3. The Legend of Zelda: Wind Waker HD: 34:49
4. Super Mario 3D World: 22:40
5. Rayman Legends: 21:12
6. Hyrule Warriors: 13:33
7. Splatoon: 6:10
8. Super Mario Maker: 5:41
9. Captain Toad: Treasure Tracker: 3:30

PS4
1. Dragon Ball Xenoverse
2. Assassin's Creed IV: Black Flag
3. The Last of Us Remastered

PSV
1. Persona 4 Golden
2. Danganronpa 2
3. Danganronpa

Nintendo

1.super smash bros u

2.mario kart

Xbox one

3.halo mcc

4.halo 5

5.rise of the tomb raider

Uncharted Collection
Resogun
Type 0
Mortal Kombat
Dust
Black Ops 3

PC:
Hearthstone
Heroes of the Storm
Diablo 3

PS4:
Resogun
Drive Club
Guilty Gear Xrd

WII-U:
Smash Bros

Xbox One:
Fantasia (fun party game)
Forza Motorsport 2

On the Wii U, I'd say Monster Hunter 3 Ultimate. For the Xbox One, Battlefield 4, followed by Fallout 4. Don't play much on the PS4, but it'd likely be The Last of Us Remastered.

Around 430hrs of Splatoon

Holy shhhhhhhhhhhoes. That's a lot of hours on Pokemon.

Xbox One:

1. Halo MCC
2. Black Ops 3
3. Batman Arkham Knight
4. Forza 6
5. Fallout 4
6. Halo 5
7. Rock Band 4