For what you described the use the 1200 would be a really nice machine.
I would also recommend thinking about a big box amiga, if you want AGA a 4000D might be a better choice if you want it to evolve into more productivity and performance. If you want to keep your options open for video cards and faster processors the 4000 will be a better choice.
If the games you wish to play are all ECS, than you can look into a 2000 or 3000.
If you decide you want an Amiga experience with the best bang for buck ratio and best modern browser etc. Morphos will be the choice. Classic Games that hit hardware will be done via emulation, which is a pain and not the best imho, but rtg games work very well.
I have never used or seen OS4 in action in person so I can't give an opinion on it.
All that being said I still enjoy my Amiga 3000 the most and use it every few days and I still enjoy tinkering with it. The classic Amigas are like classic cars and are really fun to take apart and tweek. My Powerbook with MOS is used as my daily commuter, I use if for productivity and it feels like what Amiga OS should have evolved into.
Enjoy and welcome back...
