I agree, I like Hot Space as well. Very very underrated album.
Also It's Late is probably my favourite Queen song, that or March of the Black Queen.
The Prophet's Song is oft overlooked, perhaps overshadowed by being on the same album as Bo Rhap, but it contains an absolutely brilliant vocal solo by Freddie Mercury, one of the best bits of harmonised melody Queen has ever come up with.
Ogre Battle is another favourite, Queen did some amazing stuff in their mystic/fantasy period in the early 70s, My Fairy King is another great example.
Off the later albums I'm Going Slightly Mad is a fantastic, weird and highly original track. Reportedly Freddie Mercury stated that whilst being a fun track inspired by Noel Coward comedies, it also describes the dementia he suffered from in his final years.
Also there are some unreleased tracks and b-sides that I really enjoy that don't appear on any albums, Mad the Swine for one (although it turned up as a bonus track on a re-release eventually). Also See What a Fool I've Been is really good.