If you're buying a Blu-ray player in 2011, you're probably as interested in streaming-media services as you are in Blu-ray. The BDP-S580 is a tantalizing option for a streaming-media fan, packing in more services (including Netflix, Amazon Instant, and Hulu Plus) than any of its competitors. It also has built-in Wi-Fi and an excellent smartphone application you can use to search Netflix and other streaming-media services--no competitor provides this option for searching inside Netflix.
Yet we can't recommend the BDP-S580 without a few caveats. Unlike other Blu-ray players, the BDP-S580 has its own custom user interface for each streaming-media service, and these aren't as good as the other players' interfaces. And Sony's main XMB interface can be tedious to use, especially when scrolling through all of the numerous streaming services. Since most buyers generally stick to just a couple of major services, competing units like the Panasonic DMP-BDT210 and LG BD670 that offer better navigation may be preferable. But if you want all of the niche services that Sony offers and don't mind putting in the effort, the BDP-S580 is a solid option.
Also check out our updated spreadsheet comparing all the Blu-ray players we've reviewed in 2011.