I really enjoyed The Hyperion Cantos, and the first few Dune books I read a long time ago (may reread these now). Can anyone recommend some other books (or series) along these lines? Huge stories on an epic scale, space battles, cool future tech, etc.
Alastair Reynolds's Revelation Space series is fantastic and sounds like what you're looking for.
I second this. Reynolds often uses similar technology and themes and this is my favourite version of his take on the future of humanity. Definitely epic
2nd this, great worldbuilding in the first books; and the peripheral Inspector Dreyfus books. diamond dogs etc.
IMO the latest book in the series (the final one? maybe?) Inhibitor Phase was disappointing...rehashed characters (somehow, Palpatine returned vibes) & a "grudgingly respect through shared adversities " trope that was hard to overcome.