But I also kind of take the opinion that a movie translation actually shouldn't be a 100% faithful and verbatim reproduction of the original. If everything's going to be the same, then usually I don't see the point of it all. There's been some rare exceptions (Fear and Loathing and A Scanner Darkly being good examples of being word-for-word accurate while still being relevant as a movie,) but generally unless you're bringing something new to the table with the movie, then I just don't see the point. Lord of the Rings, for example, I thought suffered a bit because they did try to stick so close to the story. I think it's a marvelous movie, and it's kind of neat seeing it visually represented - but I did get bored quite often because I knew exactly what was going to happen.
Anyway, back to the topic at hand - I just hope they don't try and condense one of the games down to a movie or TV medium if they go through with making a Fallout movie. Especially for a game like this, where every player is going to have had their own unique experiences with the game. Plus, there wouldn't be much point - any videogame movie is hoping to cash in on the existing fanbase, most of which will have played the game. What's the point in me paying $8.00 to see a story I already know?
Much better to just take the basic elements (Vaults, retro-furustic aesthetics set in a post-apocalyptic world, Supermutants, Power Armor, etc) and weave those elements into a new story that's not trying to just recap events in earlier games. If they just tried to make a new story that happens to share a common setting with the existing videogames, then I think it might hold some promise. But I'll probably forego seeing it in theatres if it looks like it's going to try and stick too closely to one of the existing stories. I might rent it later on (I rent a lot of movies, though - just to have something to watch on the weekends,) but I wouldn't hold out much hope for it being terribly good.
There's also the matter of just how good you expect a movie to be in the first place. I wouldn't expect Doom, or Dead or Alive to have very compelling storylines, for example. I enjoyed both of the movies, however, because they weren't really trying to be anything other than what they were (DOA, for example, being about the same thing the videogame is - which is having lots of scantily-clad babes bouncing around in skimpy clothes and doing lots of high kicks.) I don't hold videogame movies up to the same standards I would a Kieslowsky(sp) film or an indie movie, for example. If I saw a Fallout movie that represented the iconic aesthetic values of the game, had lots of gore, and some morally-questionable decisions (and kept me entertained along the way,) then I'd consider it a success.
Like the recent Mutant Chronicles movie - it had a lot of action, gore, and an interesting and visually-compelling art aesthetic, while at least not completely butchering the existing canon. So I consider it to be a good movie. I'd have been very suprised if it ended up being anything more than your standard sci-fi action movie fare, but I'm not going to consider it any worse for not trying to do anything more than that.