Definitely the Sims 2. I loved the Sims 1, but the Sims 2 massively improved on that game to the point I don't need to play it anymore (I do miss the really wackiness of it though, especially Makin Magic). The Sims 3 I had a go at playing, but I just didn't like it or the direction it took. I wasn't that bothered by the open world tbh, but I really didn't like the rabbit holes and the fact you can only play one family per world. I'm definitely a rotational player so that sucked. That said the EPs look fantastic so maybe my opinion would've changed had I stuck around (I was a student and didn't have the time or money to buy/play EPs). Even still, IMO the Sims 3 is miles better than the Sims 4. S3 isn't a bad game, I just personally didn't like the new gameplay aspects.
But back to the Sims 2, everything about this game is amazing. When I got the base game as soon as it came out, I was blown away, despite it only being the base game and we had less stuff than the complete Sims 1 id previously played. The way it handled generations and family play was fantastic. The expansion packs were also amazing, they had so much to do and many of them brought brand new ideas to the series (university, seasons, Freetime, apartment life etc.). I still play this game and I barely ever get bored, and I'm still finding new stuff to do I didn't know about even after 14 years. The stuff packs were also pretty good, they went with a purely decorative theme instead of trying to pad out gameplay, and filled out those themes really well and gave us so much creative choice when building. The sims themselves are the deepest sims we've had in the series and they're so fun to play. We were also given a lot of creative freedom and choices and we could do almost anything we wanted. Most of the gameplay elements were very well fleshed out too.
And regarding the graphics, I don't think they're that bad really. I mean the sims themselves do look dated, but I can look past that because they're so much more advanced that ones we've had since in terms of personalities and behaviour that it balances it out and they don't feel dated to play. They also move realistically and look much less cartoony than S3 and 4. Aside from that, the graphics for everything else (objects, walls, floors, pets etc) aren't that much less advanced than the Sims 4, OK they are slightly but the Sims 4 (and 3) hasn't made massive graphical improvements and are quite low end for today's standards. They don't look significantly better to me, just slightly. When the Sims 2 came out, the graphics were quite powerful for the time and I had to upgrade my computer to play it. It looked truly stunning in 2004 and like the devs really pushed the graphical boat out, another reason why I was so impressed with it.
