Xantrex Mobile Power Inverter
This product works good. I have used it only once so far. The price is acceptable too.

Long distance driver with kids
Unit has the juice to power the wife's laptop and the kids' DVD player though I got nothing out of the USB plug even when everything else was unplugged.

Good small inverter for only a handful of electronics
This inverter is usually OK for powering my laptop inside my car, but if I don't keep the screen brightness set very low, my wireless card turned off, and my computer set in "power saver" mode (a Vista thing), then my touchpad goes buggy after a while, and movement becomes erratic. Also, the strain of having my computer plugged in while the battery tries to charge is simply too much for this small unit, so I must either charge the battery before use, or remove it prior to use in order to prevent shutoff.

While the small amount of power provided limits this inverter's range of useful applications, its tiny size and affordable price tag make it desirable for lighter tasks, such as powering a cell-phone charger inside one's vehicle or plugging in smaller electronics, such as a battery charger, DS charger, PSP charger, etc.

The biggest advantage (IMO) that this inverter has over comparable inverters is that this unit has low voltage shutoff to prevent battery drain, and a simple indicator light to tell you whether everything is OK (blue light) or if something is wrong (red light)

warning about motorola phones
The product has a USB port but it is not compatible with my Motorola phone, the phone says unauthorized power supply and disconnects.
Works with ipods but I think the Motorola expects a "smart" usb port it can talk to and this must not be one.

Works as expected
Got this for a road trip from San Diego to LA to charge up my cellphone. It worked great at the beginning.
After one hour into driving, my cellphone started making noise indicating the power was connected/disconnected. Unplugging and replugging the charger made the symptom went away for just a brief moment. It seems like the power went on and off repeatedly. I am not sure if this was caused by the inverter or the cellphone charger, but I've never had any problem when the charger was connected to the wall directly.
As noted in other reviews, the power indicator is not bright enough to tell if the unit is on. This is especially true when driving under the hot sun. And it gets really hot when operating.