Thomas Hardy is not quite as universally appreciated as Jane Austen or Charles Dickens. I think in general people are either hot or cold about his work as it is often on the, well, depressing side. Personally I enjoy a good piece of tragic tragedy of tragicness so Thomas Hardy and I get along just fine.
Under the Greenwood Tree: Also known as the only cheerful Thomas Hardy novel. The 2005 Masterpiece adaptation is equally cheerful, though I confess it is also not very memorable in my opinion. It needs more tragedy!
Cast cross over: Keeley Hawes
Far from the Madding Crowd: In this case, I think the older version from 1967 is the best version so far. The 1998 version is all right, but I think it's a little miscast, especially Bathsheba (kind of a problem). Apparently, there's a new one coming in 2014 so we'll see how that turns out.
1998 cast cross over: Nathaniel Parker, Jonathan Firth
The Return of the Native: There's only one version from 1994, made by Hallmark of all
Cast cross over: Steven Mackintosh
The Mayor of Casterbridge: This is one of my favorites of Hardy's novels and I very much like the 2003 miniseries as well. The cast is great, especially Ciaran Hinds, and it's very faithful to the book. Such tragedy! Alas.
Cast cross over: Ciaran Hinds, Polly Walker, Juliet Aubrey, Jodhi May, David Bradley, James Purefoy
HP Bonus: David Bradley
Tess of the d'Urbervilles: Talk about tragedy! Poor Tess. Anyway, this is another of my favorite Hardy books, and there are actually a few adaptations out in the world as well. There was a movie made by Roman Polanski in 1979 that I find a little dull, though it's a faithful adaptation. My favorite is the TV version from 1998, which is faithful and also has the best cast out of all of them. Masterpiece did one in 2008 but I found it underwhelming through and through (though I guess it gets some kind of points for featuring two different Mariuses).
1998 cast cross over: Justine Waddell, Oliver Milburn
Jude the Obscure: Alas, poor Jude, he has no good film adaptation. There's a miniseries from 1971 which is, well, exactly what you'd expect from the 70s, plus a surprising amount of nakedness (that Sue just won't be contained!). There was also a theatrical version made in 1996, but I'm sorry to say it's not very good either (and also features much nakedness). Not only does it cut all kinds of plot, the cast is distractingly wrong. Have I already said alas?
So, like I said, Thomas Hardy does not seem to have the same appreciation as Austen or Dickens--at least judging by the quality (and number) of adaptations. Maybe one day we'll get a good Jude and we will all be weeping in the corner by the end of it.