Pete Pardo with Sea of Tranquility posted a ranking of the Rush Albums and asked for others in the comments.
So here's mine. the 1st 14 are quite close, which speaks as much for their quality and consistency as anything else.
1. Hemispheres
2. A Farewell to Kings
3. Permanent Waves
4. 2112
5. Grace Under Pressure
6. Caress of Steel
7. Moving Pictures
8. Signals
9. Power Windows
10. Presto
11. Hold Your Fire
12. Counterparts
13. Fly By Night
14. Rush
15. Roll the Bones
16. Clockwork Angels
17. Vapor Trails
18. Test for Echo
19. Snakes and Arrows