I'm partial to the Mars series, as they were my first, but they are a bit dated (in the same way that older science fiction generally is), and are pretty big.

Of the ones I've read / listened to recently 2312 and Aurora are both very future space based, and have lots of advanced tech involved, while New York 2140 is based in NYC and focuses way more on the political and environmental changes after 50' of sea level rise.

I enjoyed all 3 quite a bit, so it's hard to say, but Aurora and NY 2140 are really stand alone reads, while 2312 shares a lot of the themes, tech, and events of the Mars series (but it's not set in the exact same timeline, so you could read it without reading Mars).