1. Eon by Greg Bear (and its follow-on, Eternity)
Great sense of wonder SF on the grandest of canvases. The plot seriously holds attention while characterisation is not bad, at least for the major characters.
2. Quarantine by Greg Egan
Cowen prefers "Permutation City", Egan's 'reality is computation' novel (cf Dust Theory), but the many-worlds interpretation of QM is so compelling a setting and the private-eye thriller-based plot so convoluted that I felt compelled to buy this novel twice.
3. The City and the City by China Miéville
Cowan prefers "EmbassyTown" which is clever but, for me, less involving. The City and the City has a most unusual setting, the only novel I've read centred around the social construction of reality - and while the police procedural plotting and characterisation is a bit clunky, the whole book amazes throughout. The idealism of the premise is capped by its superpowered final denouement, a brutal assertion of materialism.
It's shortly to be a four part series on BBC2 (April 6th 2018).
4. Hyperion (and its three successors) by Dan Simmons
Cowan agrees with this choice. The four novels are beautifully written, have cultural depth and immerse the reader. Some of the scenes are truly shocking.
5. Altered Carbon by Richard Morgan
The story of brutal but fundamentally moral Takeshi Kovacs. The successors are good also and complete the exploration of Morgan's interestingly-complex protagonist. Warning: high levels of sex, torture and violence throughout; most characters lacking in personal empathy .
6. The Mote in God's Eye by Larry Niven and Jerry Pournelle
The writing is clunky but the plot and setting completely compelling. You won't read a better account of first contact. The style is a bracing antidote to a public culture of suffocating high-mindedness.
7. Accelerando by Charles Stross
Hits you hard and then accelerates. A convincing and baroque invocation of the Singularity: never bettered.
8. Mindbridge by Joe Halderman
People usually quote "The Forever War" which is good, but Mindbridge hits more of my buttons.
9. The Reality Dysfunction (and successors) by Peter Hamilton
Hamilton's later door-stoppers have proven tedious, but the Night's Dawn Trilogy brims with energy and inventiveness on the grandest of scales.
10. Tactics of Mistake (and follow-on Dorsai novels) by Gordon R. Dickson
Intelligent and exciting, intricately plotted with overtones of mediaeval chivalry. Loved them all.
11. The Three-Body Problem trilogy by Cixin Liu
The writing may sometimes be rather pedestrian, as Cowen observes, but the three volumes are incredibly inventive.
12. Starship Troopers by Robert Heinlein
Starship Troopers: last but not least. It's the only Heinlein novel which makes the cut for me, impressing by force of conviction. The author profoundly cares about the message of the novel and it's another antidote to contemporary hand-wringing.
Putting aside the occasional bouts of didacticism, it's a great story too.
Solaris is brilliant - I'm also a fan of Lem's other works such as His Master's Voice and The Invincible.
As a child I loved Isaac Asimov's Foundation trilogy and Frank Herbert's Dune sequence but, like Cowan, coming back to them I find they're not brilliantly written.