I'll go with the original PlayStation. There's just something about that gen and its games that is precious to me.

My top 5 games for the console would be:

1. Final Fantasy VIII
2. Metal Gear Solid
3. Castlevania: Symphony of the Night
4. Crash Bandicoot: Warped
5. Resident Evil

For me, it's the original PlayStation just for the bootup screen

But, it's still my favorite Sony console. I have so many amazing memories for that thing! But not for the same type of games that many associate with the console like Final Fantasy VII or Metal Gear Solid because my mom never would get me those kinds of games lol but the top 5 for me are

1. Tony Hawk's Pro Skater
2. Crash Bandicoot 2
3. Colony Wars
4. Croc: Legend of the Gobbos
5. Wipeout XL

Then as for 5 honorable mentions in no order

Hot Wheels: Turbo Racing
The Emperor's New Groove
Spyro the Dragon
Spider-Man
Dino Crisis (cousin gave to me in secret)

ps2 and it isn't even close. There wasn't a game the ps2 didn't have with the exception of Nintendo. The ps2 had everything.

PS2
1. Final Fantasy X
2. Ratchet and Clank
3. God of War
4. Jak and Daxter
5. Grand Theft Auto Vice City

I was pretty torn between voting for the original Playstation or PS2.  I ended up voting for the PS2 solely for its backwards compatiblity being able to play all my PS1 games.  I also used it as a DVD player quite a bit back then as well.  But as I look directly at the software libraries of the two, I think that I enjoyed the PS1 games a bit more.  Metal Gear Solid and Final Fantasy VII were absolute must have system sellers.  And titles like Suikoden, Lunar, Vandal Hearts, Vagrant Story, Final Fantasy Tactics, Ogre Battle, Vanguard Bandits, Wild Arms, Medieval, Monster Rancher, etc soaked up countless hours of my time in addition to the annual sports titles I was playing back then (Madden, NHL, etc).  There were a lot of games that I enjoyed on the PS2 (Shadow of Colossus, Gran Tursimo 3 A Spec, Kingdom Hearts, etc), but I don't have quite the same nostalgia for them as the PS1 games.  And the major third party stuff like Grand Theft Auto III ended up on XBox as well anyway.  It was the outrageous price of the PS3 drove me away from Sony hardware, and I ended up enjoying the first party games (Halo, Gears of War, etc) in addition to all the multiplats (Elder Scrolls, COD, Madden, etc) on the 360 that I never felt compelled to get a PS3 later.  By the time of the PS4 and XBox One launch, I was already invested into the Microsoft ecosystem.  I waited a year for them to ditch the Kinect, so that there wasn't a price gap to figure into the decision.  XBox Series X and PS5 are equally impossible to find in my area, so I haven't had to choose between the two yet.  And with how versatile the Switch is, I haven't been in a hurry to either.

Not in order

Resident evil 4
God of War
Final fantasy XII
Shadow of the colossus
We love katamari

PS1 for me, in no particular order:

Crash Team Racing
Castlevania: Symphony Of The Night
Resident Evil 2
Silent Hill
Ape Escape

PS4
PS1
PS3

In that order. I can't say on PS5 yet as it's still too new. I have no attachment to PS2, just Dreamcast, and Xbox that gen.

Halo

Now that is indeed a poll I had never seen coming. Let me do the rundown:

1. PlayStation 3
2. PlayStation 4
3. PlayStation
4. PlayStation 2

First and second place is a close-call. If I had gotten Persona 5 on on PS4 instead of 3, it would probably be my top pick, as that is essentially my favorite PlayStation game ever. Other PS3 favorites would be The Last of Us, MGS Legacy Collection and Tales of Xillia, Xillia 2 and Graces F.

Can't speak for PS5 as I don't have one or have tried any of its games.