I have been using ZoneMinder for a couple years now, and I've always had good experience with it. For the cost (free!), you just can't beat the features - most commercial video surveillance solutions don't even come close. Anyway, while it has always worked well, I was never quite satisfied with the web interface - so I have been working on a new one; something more modern and end-user friendly.
Please join in on the discussion - remember, ZoneMinder is The State of Linux Security DVR Software and it will only get better with your input!