I'm new here too, but I'll attempt to answer what I can.
The Dell drivers are pretty much the only way to go in my experience as far as the video is concerned. Personally intels oem drivers wont even install for me, says I don't meet the system requirements.
On my desktop the CCCP codec package has proved to be the best on multiple fronts. Not only would it seem to be the most efficient, but it also provides for the best picture quality from what I can tell. It will come with a choice of 2 media players, personally I like MCP-HC as it's fairly light weight and simple. - Now on battery I do get a bit of lag currently - processor running at 700mhz just isn't enough to chew through some video I guess. On power it seems to be fine though.
I just reinstalled my OS, I REALLY didn't feel like trying to figure out what all clutter Dell stuck on here.
As far as the car charger goes, you can get an inverter from Wallmart for $20 - $30 that will allow you to use any standard American AC plug in your cars DC cig lighter. Very convenient.