My daughter used the Wii, rather than the Xbox, to sream Netflix, but got tired of waving around the controller at a clumsy on-screen user interface and bought a cheap BlueRay player for the task. A Roku or other streaming-only device may be less expensive than a BlueRay if you will never use the disks.
I find that my iPad, and my Windows laptop, are both superior to my BlueRay.player for NetFlix, in terms of image quality, maintaining aspect ratio, support of features like closed captioning, and the interface for finding shows and managing queues. This is about the qualty of the Netflix apps for iOS and the web browser vs their app for Java devices like the BlueRay player. This situation could be different for the apps for other services like Hulu or Amazon, but if you have a moden laptop with HD video and HDMI out, you might try it as your video streaming device. For non-HD, Wii or Xbox 360 can be adequate, if they support your choice of streamed TV.
You need to have a fast enough Internet connection, and a data plan that supports the volumes. I found 500 kbs to 1 mbs adequate for standard definition, 3 mbs will handle streaming at least one channel of HD and still save some room for other active, low volume connections on the same service. But your service has to sustain those speeds; some providers offer outrageously high connection speeds that are just burst speeds on their connection, not sustained, and not going that fast across the Internet to whatever services you are using.