If you are looking for a job in professional OEM automotive, ARM is your only option for entry level training that means anything. I don't know of any PowerPC starter kits, which is another big one. dsPIC is certainly a capable chip, there are a lot of capable chips out there, but dsPIC on your professional resume will get you about as far as Eagle experience in professional PCB design, which is to say not far.
There is an abundance of ARM starter boards, but ST, Freescale, and NXP are the most popular.
Most high level systems in automotive (ECU, air bag control, ABS brake control, stability control,...) use some specialized chips that are certified for automotive use.