Game of Thrones goes downhill very fast. I loved the first few mind.
Just re-reading Peter F Hamilton's Night's Dawn trilogy, it's horribly written and paced but still, when it's good it's good, proper holiday blockbuster stuff. Should have been edited with an axe not a pen, though. Slow in places so might not hit your mark. Night's Dawn is his best idea but the older Greg Mandel novels are written better.
And yeah, if you've not already, Iain M Banks, when he's good he's very very good.
Little bit off the recommendation but I just went through Ben Aaronovitch's Rivers of London in record time, it might appeal- a cross between a police procedural and a magic-n-monsters fantasy, in present day London. Loads of fun.
Straighter fantasy- Joe Abercrombie, master of the new fantasy subgenre made popular by George RR Martin, "fantasy in which absolutely everyone is a dick". Absolutely revels in it, The Heroes is maybe the best example but The Blade Itself is probably the starting point. Maybe getting a wee bit repetitive/formulaic now.