I have two of the non-interactive style -- one for cycling and one for other purposes (like when I walk to the gym). There's enough room on them for the information I need to include with one line left over:

My Name
My City, State USA
Parents xxx-xxx-xxxx
Sister-first-name xxx-xxx-xxxx Sis
asthma/allergy info
WHAT WOULD JENS DO?

If you need more space for medical information, you could use both of the last two lines.

For things like insurance info and doctor contact info, I don't want them on the Road ID because they change too often. I keep that information in my jimi wallet in my bike bag, which I imagine would be found and used eventually.

I would only switch to the interactive version if I had important medical information that did not fit on the regular version.