PS2 or PS3

Wii U

PS4

Xbox 360

Based on it's own library of games (no ports, collections on other consoles down the road etc)

SEGA Megadrive.

DS. No explanation necessary.

Gonna break it down for you.

8th gen:  I own the Wii U, PS4, Xbox One, 3DS, and Vita.  My favorite is the Wii U (right now)

7th gen:  I own the PS3, Wii, Xbox 360, PSP, and DS.  My favorite was the Xbox 360

6th gen:  I own the GBA, PS2, Dreamcast, and Gamecube.  My favorite was the PS2

5th gen:  I owned the N64 and PS1.  My favorite was the PS1

4th gen:  I owned the Gameboy, Super Nes, and (years later) Genesis.  My favorite was the SNES

3rd gen:  I owned the Nes.  My favorite was the NES.

2nd gen:  I didn't own shit.  I played some Atari, though.  I loved Atari.

And my favorite of all time?  It's a close race between the Super NES, PS2, and the Xbox 360.  Super NES because of the age I was at the time and the leaps gaming made.  PS2 because games finally looked and felt the way I always dreamed they would (and I had a ton of them!). Xbox 360 because I had a fuck ton of money and that console game me a ton of joy.

My favorite (possibly fueled by nostalgia) is the Super NES.

Console: PS2

Handheld: 3DS

Overall: PS2

PS2

I'm gonna go with N64, but it's hard for me to really decide. I'd throw the GameCube, Wii and PS3 up there too.