I was recently bought Don't Starve by a friend. I haven't had much time to play with it, but it looks promising, and I love the aesthetic. It's a survival game where you find yourself stranded in a bizarre new world and need to gather the supplies and build the items you need to last against the monsters that appear. Most importantly, you need to make sure you don't starve.
Bastion and Transistor are definitely great buys. The gameplay is clean, the art styles are charming, and the music is fantastic. I could listen to the OSTs of both for hours. They're both completely different games, in story and in gameplay, but both are action games set from an isometric viewpoint, and I love 'em a great deal.
FTL is a great little rougelike where you manage the crew of a spaceship as you race across the stars, away from a fleet of rebel ships. You jump from system to system, investigating them for supplies and equipment to help you get back quickly and to fight off the various pirates and rebel ships that stand in the way. Rather than control the ship, you specifically control the crew from a top-down perspective, guiding them towards parts of the ship to manage systems and repair damage.