Active has a lot of advantages over passive, each driver with its own matched amplifier, an electronic crossover that isn't powered by the amp, etc. Its really only disadvantage is wiring, the need for signal and power to each speaker. However, I wouldn't pass up a good passive over a mediocre active speaker. The overall design is important and that needs to be considered.
Note that if you don't get an A/V receiver you'll still need many components that usually are found in a receiver. This includes one or more multichannel DACs, a device that does the DTS Neo:X upmixing, and, if you want to use multiple sources, some kind of input switcher.
Of course you can still get a receiver and only use pre-outs. This is the easiest (and only?) way to solve the aforementioned problems, but it does kind of negate the 'not needing an external amp' advantage.