Agreed. You can then move forward into the 80s for more of a synth-rock sound, or backwards to the 70s for a more prog-rock sound. Choose your own adventure.
I started with 2112. Any of the following are also good exploring: Permanent Waves, Signals, Hemispheres, A Farewell to Kings, Clockwork Angels (newer) and probably the most well known Moving Pictures which has already been mentioned.
It really is choose your own adventure. I wouldn't say every Rush record is good (some are just okay, none are outright bad), but there is something good to take away from every one. They had a fantastic run.
If you have Netflix, check if the documentary "Beyond the Lighted Stage" is still on there. Its a great doc and gives you a glimpse at the different eras/albums. Personally I like Hemispheres, Moving Pictures and Fly By Night the best.
I agree with everyone else. The entire run from 2112 through Moving Pictures is extremely good. Moving Pictures is my favorite but 2112 and A Farewell to Kings were the two albums that turned me into a vinyl collector.
Lately I've been into their other 80s albums too, but it's fair to say anything past Moving Pictures is more of an acquired taste because the production choices are sometimes absurd.