Re-reading the Larry Niven Ringworld series. I'd clearly forgotten a few things!
I reread most of his "known space" books a few years ago (including some of the novella's I'd never read before), and really enjoyed them, especially as it was the first time in 10+ years for most of them and I was picking up all sorts of bits I'd missed/forgotten and comments/references to the stories I'd not read before made sense.
Second book in to The Collapsing Empire trilogy by John Scalzi. Very accessible sci-fi, ploughed through the first book in no time. Bit space opera, few funny moments and some good twists. Really enjoying it.
He's one of my favourite current authors*, the Collapsing Empire series is really good fun and I love some of the characters (Kiva is great).
If you've not read them his Lock in/Head On books are very good (there is also a short story that is set before them basically telling the story of the Haden virus), whilst the Old Man's War series is fun action sci-fi
I'm currently alternating between various "light novels" that had anime based on them (they're very fast/easy reads and I often find myself muttering "these are bad, but so fun"), and rereading Ann Leckie Ancillary/Imperial Radch books which are really good, basically the story of a member of the military of a multi world civilisation that realises something is wrong and starts to to take action on it's own (I'm trying not to say anything that could be a spoiler), it's great.
Raven's Tower which is her non Radch book is strange but also extremely good, it's told from a viewpoint you don't really expect).
I'm tempted to reread Peter F Hamilton's "Salvation" books ready for the final one in the Trilogy which is due out in about 8 weeks, as he's another of my favourite authors (I was so excited to see one of his shorts when it was made into one of the "love, death and robots" episodes on netflix).
He had a habit of making some truly huge theatres for his stories, often set across multiple worlds and decades, if not millennia (his Prime dualogy ended up being the start of 3 separate but linked stories), and a cast of characters that could give GOT a run for it's money.
*Which means he'll probably end up dying in a freak burrito related accident soon (my favourite authors seem to have a habit of dying a couple of years after I realise they're my favourites).