IGX

Best hundred bucks I've spent lately. Dropped U-Verse when my bill was going to hit $180/month, now I've got Netflix, Amazon Prime, HBO Go, MLB TV, UFC.tv (PPVs are cheaper than they were via cable), PBS and a wide variety of other channels. The box is tiny, maybe four inches square and two inches tall, connects to the TV via HDMI, I've got it wired directly to my router for best quality but you can run it over Wi-Fi.

I've been running a Plex server from my desktop to the Roku - quality with 720p or 1080p MKV files is iffy (your server has to transcode on the fly), but XMedia Recode will re-encode a MKV to MP4 in a few minutes and then quality is every bit as good as a Netflix HD stream. Not quite the sharp pop of a BluRay but it looks good on my TV.

How do you get HBO Go without a cable subscription?

I use a friend's account via U-verse.