I really wish there would be support for .avi and .mkv
I was thinking the same thing. I have a huge collection of mkv. But I will say they are mostly high quality 1080p with flac audio, which would amount to 10gb and up for streams. Probably not a good idea for a beta site.
There's also the problem of not being able to use subtitles on foreign films, which limits what movies can be added. But I'm sure in time they will fix these little problems.