That's becoming one of the best reasons to choose Playstation these days, unfortunately. They're ditching backward compatibility and losing exclusives right and left (first Assassin's Creed, Devil May Cry, GTA, now Final Fantasy). Now the Xbox 360 has Netflix streaming. I switched from Netflix to Blockbuster.com because I loved being able to have my cake and eat it too (instant gratification by swapping movies at my local Blockbuster). I always loved Netflix, but Blockbuster just offered something Netflix couldn't. But I gotta admit, streaming directly to my TV is even more instant than access to the local video store.
I won't be getting either in the near future, but I have to admit that Microsoft is doing a pretty impressive job. If I were buying today I'd still get a PS3, but I'm not sure that will be the case when I can actually afford to buy one.