I got my EMT cert soph year, then took a semester off junior year to work full time in LA. It is a pretty awesome job if you get to run 911, especially in a place like Inglewood. You'll see the craziest stuff. I'm not an adcom, so I won't tell you whether or not it'll get you into medschool, but it definetely qualifies as good clinical experience, gives you something to talk about in essays/interviews, and proves to yourself you can handle pressure situations and that medicine is the field for you.
BTW, those non-911 calls actually can be pretty interesting too. About 25% of the calls I ran were interfacility transports, which yes, often went to convalescent homes. But, some of them were to neo-natal clinics, burn units, etc. Also, since those retirement homes are pretty crappy, especially in LA, those calls can get pretty interesting. Twice, we've had a patient code in the middle of a "boring IFT". Definetely, I prefer 911, but you can still get something out of non-emergency calls, especially since you end up running the show, not a paramedic.
I'm glad I did the EMT thing, though I never want to do it again; pay sucks, get treated like dirt, long hours, no respect.... But I was pretty proud of my experience through the application process.
If you have any specific questions, feel free to ask.
GO ORIOLES!