You know the feeling: You roll out of bed and you need your caffeine fix now. That's where the best Keurig coffee maker comes into play. These single-serve machines are famous for their speed and user-friendliness. They make just enough for one cup: No more brewing a full pot only to let it sit ... and sit ... and eventually dump it down the drain. We tested five popular models, and we found one that can brew it all.About 45 million households across the United States and Canada have a Keurig coffee machine. It's no wonder: As far as single-serve coffee makers go, they're affordable, starting at around $90, and they go on sale often. Just know that you're paying for convenience, not necessarily the best coffee taste (for that, consider one of these great espresso machines). That said, you'll never lack variety when it comes to Keurig coffee pods, called K-Cups. Major brands including Starbucks and Dunkin' make all kinds of K-cup coffee, from flavored blends to dark roasts. Even celebs have gotten in on the game (hey there, Kevin Costner).