By now most people probably have the Iron Throne we see in the HBO series Game of Thrones firmly in their mind when they picture the throne of Westeros. But Martin has said, it's still not quite right.
He recently posted an image from artist Marc Simonetti for the upcoming The World of Ice and Fire book to show what he thinks the Iron Throne should look like. I have to say, it would definitely be awe inspiring to see it like this in the show.
“It’s a rough, not a final version, so what you see in the book will be more polished. But Marc has come closer here to capturing the Iron Throne as I picture it than any other artist to tackle it. From now on, THIS will be the reference I give to every other artist tackling a throne room scene. This Iron Throne is massive. Ugly. Assymetric. It’s a throne made by blacksmiths hammering together half-melted, broken, twisted swords, wrenched from the hands of dead men or yielded up by defeated foes... a symbol of conquest...”
Very similar to an earlier painting from Simonetti (you can see more of his work on his deviantart webpage) pictured above.