I know this isn't something you're supposed to admit to, but I certainly do judge a book by it's cover. If I've already heard about the book or been recommended it it doesn't matter so much, but if I'm browsing unknown titles I'll shy from covers with photos, that cartoonish style prominent in chick-lit or amateur-ish or over-the-top photoshop graphics. They might be fantastic books, I have no judgement against the author, I simply squirm whenever I see a cover like that. I think it is one of the reasons I shy away from the paranormal YA and adult fiction that is so prominent at the moment (that and the links I am constantly making between them and Twilight). Perhaps another part of it is that I see some of those graphics as linked with romance fiction (of the Mills and Boon variety) and I certainly don't want anyone (even strangers on the bus) to paint me as a romance reader and I guess that reflects back worse on me than it does the books.
The covers that catch my eye generally have very little in the way of graphics or images, I love covers that have large text (like the Cormac McCarthy cover above) or block colours (the Popular or classic Penguin) and I think that's partly because those covers don't tend to date and look trashy like pictures can, but also because that particular aesthetic appeals to me. Some of my favourite book covers in my bookcase are from the 50s/60s/70s and have bright and bold abstract patterns (on a paper cover which also is a preference of mine) which reflect very little on the content of the book, but age magnificently.
Back to the movie editions, part of my disdain, apart from the photographic cover it invariably has, is that I feel like it cheapens the book. It places the prominence on the movie rather than the original creative work and becomes just another marketing ploy to sell more tickets. It always has "Now a major motion picture starring X" emblazoned across it, and usually a nice big picture of the lead actor right in the middle. Most film adaptations, even the ones we all respect and enjoy, shift from the book's original content and I feel like when the movie poster is put on the cover it is heralding the movie version of the book over the original author's intention. When I was younger I always wondered whether those editions were the original text or the text altered to fit the book. Wouldn't you be pissed if you'd loved a film and bought the book only to find it was extremely different, and then where does the blame go?
Perhaps I don't really have a rational reason to dislike movie editions, and perhaps it is purely because I'm extremely shallow when it comes to which book covers go into my bookshelves but I just can't pick a movie edition when an original cover version is available. I had to hunt for a copy of I Am Legend for months to find an edition that didn't have Will Smith walking across the front, which meant avoiding cheaper second hand copies because they were the movie edition and ultimately paying more so that I could get a cover that had the graphics I liked on it's cover. Maybe that's crazy but that's me!