[Bluestein]

That's very categorical. Full stop :)

Must be really good.-

[mpalmer]

I read them all in the last year and have since been searching dejectedly for something that comes close.

Indeed, it's excellent. Banks created something singular with the Culture, and he brings it to life with wit, energy and impressive imagination.

[adeeshaek]

The polity novels by Neal Asher scratch a similar itch - the polity is much less utopian than the culture, but the world building is quite similar. I would recommend the Transformation arc as a good starting point!

[lucubratory]

What order would you recommend reading the polity novels? I'm thinking about starting them

[squigz]

I have to second GP in saying it is, by far, the best scifi I've ever read.