It doesn't happen daily but I have noticed that it usually occurs when the unit hasn't been rebooted in a while. It might be the channel or the stream itself, but not sure. I know my Roku works best after a reboot but it takes an awfully long time to initialize. I have requested some sort of over-night reboot scheduling and updating function so the unit works best and goes through this cycle when not in use but not offered yet. Maybe something like this can be accessed through "secret" advanced menu in the near future.
This is my setup: Roku 2 XS on Ethernet, 8GB Micro SD Card, 50MBPS Ethernet and 25MBPS (WiFi on Wireless G Band-For Compatibility purposes). All 3 of my Roku's choke from time-to-time: (2) Roku 2 XS and 1 Roku 1 (New model). Again, not a daily thing but it is a bit annoying having the thing choke in the middle of watching something and waiting for a long reboot to then re-find and play what you were watching.
I have done ping tests on my network to check for lost packets but no packets lost so this may not be the problem. Given I have cable, I don't always have full 50MBPs speeds but even during peak hours I have over 25 which is more than enough for streaming without re-buffering. My Blu-Ray and Google TV boxes work fine so I doubt it is something with my network.
I could change channels on my router to test for stability but that is for the WiFi. That should not affect my 2 XSs that are connected via Ethernet.
Maybe you can say it is the SD card but my Roku 1 doesn't use them and also chokes so that either. Am I missing something? What is left is the Roku itself (HW limitations) or software related (Firmware, channel itself, or actual streams (source).
(2) Roku2 XS,Roku 1(New),Logitech Revue Google TV,Raspberry Pi+XBMC,Mac Mini HTPC-EyeTV DVR+Rabbit TV+PLEX+XBMC,TiVo Premier,Wii,PS3,Sony Blu Ray w/ streaming apps,Equiso Android TV
Local TV: QAM from ISP coax line. PLEX+unsupported plug-ins.