I think the 1984 adaptation is extremely good, especially given its budget limitations. The look of Oceania - a bombed-out mixture of WW2 Britain, Germany and Russia - is spot on. Everything is rotting and broken. It's also a very grim and depressing experience, like Threads or a documentary about the Holocaust. Basically, it's a very convincing depiction of humanity at its worst.
A couple of small things: John Hurt looks really ill for most of it and nearly dead towards the end. He is pretty much as I imagined Winston Smith. Secondly, the film has the characters address each other as "brother" and "sister" instead of "comrade". I think this is a good idea, as modern viewers probably see "comrade" as purely Soviet. It was also used by Nazis.