Visual inspiration: John Berkey, Ralph McQuarrie, Syd Mead, Doug Chiang and Stephan Martiniere.
While we could rave at length about any number of epic space operas, we have exercised great restraint and listed a few of our favourite ones here. However, this short list does cover a wide range of styles and epic civilisations.
Arthur C. Clarke -- 2001 : A Space Odyssey. Arthur C Clarke's 2001 : A Space Odyssey is perhaps the most famous of all Space Opera stories. In 1968 Stanley Kubrick directed the film that still stands as the most astounding achievement in both predicting the future and advances in film effects. The original novel was followed by 2010 : Odyssey Two (also made into a film), 2061 : Odyssey Three and just recently 3001 : The Final Odyssey.
Isaac Asmov -- Foundation Trilogy. This spans the length of the Galaxy starting with the fall of the Galactic Empire and ending with the Second Foundation. Many images have been inspired by the city-planet of Imperial Trantor. This site has a nice collection of images from book covers http://www.slawcio.com/foundation/cover.html
Greg Bear -- Eon. Greg Bear has created an entire linear universe The Way spans from now to the end of time. It is a tubular universe created around a linear singularity. The Way connects to many systems in the outside universe and is used by various civilisations. At it's terminus The Way is blown out to create a vast closed universe strung with folds and loops that are inhabited by vast civilisations.
Frank Herbert -- Dune. Starting with the initial Dune book the universe created by Frank Herbert is now documented in 11 prequels in addition to the initial 7 books Frank Herbert wrote! This epic tale spans 10,000+ years and tells of a universe through they eyes of two powerful houses Harkonnen and Atredies. As the universe evolves it is changed by the ability to travel faster thank light. Folding space the navigators and the spacer guild are a powerful force. However In Dune Frank Herbert focus vast Galactic conflict on a barren planet Arakkis that is the sole source of Spice Melange that enables the spacer guild to navigate folded space safely. Arrakis is the stage where Frank Herbert weaves an epic tale of politics, mysticism, intrigue and sheer adventure.
Steven Baxter Timelike Infinity, Flux, Ring and the Maifold series. Steven Baxter has degrees in Mathematics and Engineering and it shows in his works. Sometimes hailed has the pre-eminent of current SF writes Stevens novels span not just galaxies but entire universes and even all of time and beyond? There are few authors that can create races such as the Xeelee who build structures not from planets, or suns, or even solar systems, but from myriads of galaxies!
Orson Scott Card Enders Game. For epic space battles nothing comes close to Enders Game. Orson Scott Card is one of SF's most awarded authors. Enders Game and the sequel, Speaker For The Dead, won unprecedented number of awards and they deserved it. If it's hi-tech space battles with aliens then Enders Game is it with a staggering twist which I would spoil if you haven't already read it.
E. E. Doc Smith . Skylark, Lensman and Family d'Alembert seris. EE Doc Smith is one of the grand masters of true Space Opera. His writing career spans from 1934 1985 starting with the 7 Lensman books (1934 1960) through the 4 Skylark books (1946 1966) and finally the 10 Family d'Alembert books (1976 1985). These stories span a rich universe populated with diverse aliens and technology.
And who can forget these classic Space Operas from TV and film.