Magellan MiVue 480D.
Front and rear HD. Comes in handy quite a bit.
I witnessed a really bad accident, but unfortunately the dashcam didn't capture it because it had stopped recording 2 months prior without notifying me. Once I reformatted the card, all has been fine. This is a known concern because of the constant heat cycles, read/writes, significant amount of files being written, etc... So it comes with the territory. That being said, just keep an eye on the card and do some playback occasionally.
Friend of mine has the BlackVue or something like that, it has wireless capabilities which are pretty cool. I use an iDragon usb/lightning adapter with great success.