Let me really emphasize this. If you don't think there's such a thing as a good remake, watch the first two movies on this list. Watch the originals too if you can.
Good:
The Thing (1982): This, ladies and gentleman, is how it's done. Everything about this movie is top-notch. It's got visceral jump scares, an eerie atmosphere, psychological thrills, everything. It's one of the most terrifying movies of all time--not just for its gross-out factor, but for its intelligent stab at making the viewer feel paranoid for the characters in the film. The original is good, but it's not this good.
The Fly (1986): Another 80s gem. As with The Thing, the special effects steal the show. However, I also find Goldblum's portrayal of the main character, Brundle, sympathetic. Watching him undergo his transformation is heartbreaking, and it's something all of us can sympathize with--as we get older, we change, physically, mentally, and spiritually, and the process is rarely comfortable.
I actually love the original version of The Fly and it's not made obsolete by Cronenberg's re-imagining. Still, I feel the 1986 film improves on the original and uses its concept to explore different themes.
The thing that makes these two remakes great - along with the ones Mercedes mentioned, particularly Soderbergh's
Ocean's Eleven (2001) and Campbell's
Casino Royale (2006), and a laundry list of others such as Martin Scorsese's
The Departed (2006) - is that they are only remakes in the loosest sense of the word.
Questions like this should really ask what is meant by the term "remake" - a shot-for-shot duplication of a film is almost always going to fail, no matter how great the source material is. Gus Van Sant's
Psycho in 1998 demonstrated this, and there's a very real reason for this: duplicating the same beats of a film is a rote, mechanical process that does not take into account small little moments of truth that arise on set. Film is a very volatile medium to create within; your actors are going to find little moments that neither the writer nor director thought of prior to that instant, and you need the freedom to adapt and capture those moments. A shot-for-shot remake, even with the same actors, will not have the flexibility necessary to bring out the discovered moments of truth, and will be demonstrably lesser than the original.
So a shot-for-shot remake, which is perhaps the most literal interpretation of the term, is right out. What, then, is a remake? Is it making another film with the same script? This has happened so few times (if at all) in the history of film that I think we can dismiss this possibility out of hand. Is it simply making another film from the same source material or using the same plot? The Coen Brothers, when writing/directing the 2011 film
True Grit, insisted that their film was not a remake of the John Wayne original, but rather a separate, independent film that simply adapted the same source material. Both films are great films, unquestionably (my personal preference lies with the Coens' version). But what qualifies it as a remake or, as the Coens insist, a separate adaptation?
Ultimately the concept of remake is very ill-defined. It generally refers to a film that takes the basic premise of a prior film as its own, often borrowing the title (but not always - Scorsese's
The Departed was a remake of a Hong Kong film,
Infernal Affairs) as well. But that leaves a lot of room. A film can take that basic premise and do wildly different things with it, or it can adhere very closely to that original premise.
I posit that the best remakes are in the former category - they borrow the basic skeleton of a prior film and do something novel with it. Steven Soderbergh's
Ocean's Eleven turned the Rat Pack's caper film into a stylish 21st century heist film that hewed close to modern heist trends, glamorized white collar theft, and used an ensemble cast to its advantage. Martin Campbell's
Casino Royale (often termed a "reboot," which is an even messier affair that we won't get into) used the skeleton of a James Bond film that had come before in order to deconstruct the Bond character and strip him down to his essential masculinity, and then tear at the seams thereof. John Carpenter took Howard Hawks' bizarrely against-type horror film and shoved his own unique style into it, creating yet another horror classic. David Cronenberg took the 1958 film
The Fly and injected his pet topics of sexuality and body horror into it, creating a film that is perhaps the best example of his unique style (maybe
Scanners has that title, but
Fly is real close).
Good remakes do not simply remake, they
reinterpret. A film that is remade without having something new to say - as many foreign films remade as American films often are - is rarely substantial, often feeling rote or obligatory. While
Let Me In was a very serviceable horror film, it was not as good as its forbear,
Let the Right One In. David Fincher's
The Girl With the Dragon Tattoo, however, in reinterpreting the source material that spawned the Swedish original films, managed to create a film that not only stands alongside the original, but by many accounts (mine included) supersedes it.
Remakes aren't a "mixed bag" or anything of the sort. Just like a wholly original film (if such a thing can be said to exist; all films are influenced by what comes before), the success or failure of a remake is going to come from the talent, creativity, and inspiration put into it. Plain and simple.