I don't play my media through WMC besides my recordings and live TV. That's not what it's great at (though with codec packs and other workarounds, you can get all your media to play through WMC and have the features you want because WMC is extensible and tweakable). I have different devices for different needs. I have my WD TV Live. I have my Xbox 360. I have my Wii. I have my PCs/notebooks/tablets.
There is no great all-in-one program or device. For playing my archived movies on the TV, I use my WD TV Live. For playing my recorded shows or watching live TV, I use my 360 systems as extenders to my main PC which has the 4 tuners. For Netflix and the other streamers (like Crackle, Vudu, Hulu), I use the Xbox, the PC, and the tablets.