I saw The Hitchhiker's Guide to the Galaxy today. It was definitely good, and I enjoyed it, though I don't think it was quite as good as I had expected/hoped. Visually, it was great. The Vogons, for instance, were wonderfully Vogonic, and the inside of Magrathea was fantastic. And even the parts that didn't look quite right to me at first ended up working out quite well, e.g. Marvin, Ford, and Zaphod's extra appendages. The main issue I had was that none of the voices were right (though Alan Rickman as Marvin's voice was pretty close) and none of the lines were really delivered in quite the way they deserve to be. Admittedly though, I've always had very specific, detailed opinions on how the whole book should sound, so I'm pretty picky in that department.
Lots of stuff was cropped, of course, but I think all the important points from the book were covered. And there were some added scenes which were kind of interesting, too. The cool thing about it all is that Douglas Adams actually wrote a lot, or most, of the screenplay before he died (I think it was an ongoing project ever since the book first came out in 1979). So all the major changes like that were actually his idea. That means I'm a lot more forgiving than I usually am of movies made from books, since we're basically getting more stuff straight from the author.