Seconded on that Vista isn't that bad, and the learning curve isn't that high/hard to get over. There are some annoyances (like the UAC) but otherwise it's not that different if you want to stay in the Windows world.
If you are going to learn something new though, just about anyone could pick up a Ubuntu or Fedora based system and start working with it right away. If you were going to be starting from scratch and setting up such a system there are some very easy to answer questions regarding the configuration of the system (things such as what is the hostname/computer name, would you like the network to be automatically configured -- for most people the answer is yes, and what password would you like to use). If you feel adventuresome you can change the default disk drive configuration and make custom selections regarding what applications and tools you want install on the system, but for the most part it is very easy to choose 'Workstation' or 'Development system' or whatever the categories are (not the real names there by the way).
Once you have Ubuntu up and running, or same with Fedora and most other nice Linux builds, you find that you can work from the GUI pretty much all the time and never need to touch a command line. There are things that are easier from the command line for most people, but there are pretty much always some GUI tools you can use to do the same work with now making Linux at least as friendly as any modern Windows build, if not even friendlier.
The only negatives I would immediately chalk up against Linux would be if you are trying to run Windows based games and/or use some specific applications like iTunes. Outside of that sort of thing, Linux is again at least as usable as Windows is, if not much more so.
Finally, even though Microsoft hates it (which is actually reason enough to do it! hehheh) you can still get Windows XP on many vendor's systems as they've been forced -- by the market -- to keep allowing/supporting sales of Windows XP until the market is really ready for the transition.
On HD radio - if it's free in the vehicle sure, fine, whatever. Pay extra to get it -- no thanks. I already pay for a Sirius subscription and commercial free (for the most part) radio via satellite blows away the over-commercialized local radio around me.
HD radio seems to be slow to catch on though, and typically costs as an option, so I wouldn't expect to find it in a vehicle too soon. At least not in the average person's vehicle.