I got a Kensington mini usb car charger at Amazon for $10. It works great and does not affect any screen performance when plugged in. One plus is that it provides 700ma output instead of the usual 500 for usb chargers so it charges faster and holds the charge under heavy use.
I had the screen-gone-wild issue when using a Moto car charger inside with one of those cig lighter adapters. I wrote it off to cave man science on my part and got an aftermarket BB charger from WM that works just fine. Point being that if it's specked for BB it should work fine. Not a lot of aftermarket micro-usb chargers out there labeled for the Droid (yet).