Best way to access & play 2tb movie collection?

I have a Tivo & Apple TV and I'm curious how best to access the media on my Mac or PC. I upgraded to Tivo Desktop Plus and I am able to play a lot of movie file formats which is nice, but with Tivo the process is the movie needs to be transfered to the Tivo hard drive vs. just streaming correct?

Apple TV is nice but the media needs to be in iTunes or .m4v format. What I like about Apple TV is it is accessible quickly on wireless network and doesn't need to transfer + take-up space on another unit. Any other suggestions like a Western Digital WD TV Live Streaming Media Player? But then I'd need a WD box in addition to my Tivo & Apple TV. :confused:

Thanks,

Shane