I use a Roku, PS3 and AppleTV. Its excessive but none of them are "great" but all of them have uniquely awesome features that I need.
If you're really entrenched in the Apple Ecosystem then the AppleTV is an essential because you can access all your itunes videos as well as rent from the iTunes store and use netflix. I thought mirroring would be awesome but its not as useful as i thought because of the different aspect ratios.
But if you're looking for a more diverse product then I recommend the Roku. It has Netflix, Amazon Prime, Hulu+, Crunch etc.
Finally, the PS3 does everything i need (DLNA to stream over network, Netflix, Hulu, DVD, Bluray) but takes too much power to use constantly.
Hulu is the big deal to me because I prefer the AppleTV but without Hulu Im missing out on a lot so I have to waste HDMI ports and electricity on single function devices.