There is a huge thread on the Nexus forum about this issue. This is one charger that seems to be highly recommended. I also included a review that explains the issue with car accessory chargers. I just ordered one for less than $4 shipped.
Update: I received the charger and it charged my phone from 86% to 100% while using GPS and Pandora in about 30 minutes. I think it works better than my wall charger.
Amazon.com: HTC T-Mobile myTouch 3G Car Charger - Black: Cell Phones & Accessories
According to the USB spec, the typical wiring for standard data connection will provide 0.5amps. However, if the data pins are shorted a certain way, the USB connection can provide up to 1amp. Most, if not all smartphones, can detect this. Android phones can display one of the following when viewing the batter status:
- "Charging (USB)" = 0.5amps
- "Charging (AC)" = 1amp
When I use a standard micro-USB cable with this charger, my android phone indicates "Charging (AC)". This means that this charger appears to be wired correctly to provide up to 1amp current
Many generic chargers out there are not wired to provide 1amp (instead they are wired to the USB data spec), and will only provide 0.5amps unless you have a special cable that's wired a certain way.
Aside from the wiring, the charger itself has to be able to output 1amp. On this charger, the output specs (5v and 1amp) are clearly labeled.
All in all, a very good charger at a great price.