Gen 1 for nostalgia, Gen 3 because Ruby was just an awesome game overall.

I'm a gen wunner through and through and I'll fully admit that. I've played through a couple of others but it was just so original and it keeps things simple enough for me. I don't like breeding and micro-management and I can still go back to them while I've never gotten the urge to replay another one. Charizard is also my favorite and I have to have him in my group and hate how they don't let you do that until after you beat the game.

Gen 3 easy.

For games it's probably Gen 3 followed by Gen 2. For my favorite Pokemon it's Gen 1 and Gen 4.

Gen 3 and then Gen 1.

I'll have to say my favorite is Gen III (R/S/E). I loved the tropical setting and the soundtrack. And despite all the flaws I can list, I'll have to say Gen IV (D/P/Pt) is my second favorite. I just loved Sinnoh a lot and the mythology associated with it.

Kanto is my favorite region. Red and Blue were amazing back in the day.
But X and Y brought its A game and now I have a hard time choosing the best. Its between X/Y and R/B though.

I hated R/S when it first came out because It just felt really rushed and boring I liked the designs of the pokemon though. OR/AS got me to enjoy the region alot more than I did 10 years ago. 

Black and White is to me the lowest of the low it doesn't even look or feel like pokemon the designs of the pokemon look straight out of a little kids notebook. Oh and the ugly pixel graphics ew.

Gen 2 was the peak of the series IMO. It added a lot of cool things, like day and night, introduction of the egg, the pokegear, rebattling trainers who call you, excellent pokemon designs, battling Red from Gen 1, and 2 REGIONS. It had so much. And then gen 3 came and took that all away, only to have decent music and weirdly designed pokemon. Pokemon games after gen 2 couldn't reach what Gen 2 did. Maybe X/Y came close.

I guess I should've said additions. Day/Night came back, the sprite movement looked a lot better, it was "3D" (The field at least), and online became a thing (from GTS to easier to get events to battling).

And they introduced Day and Night mechanics too! It's not just aesthetics.