Hi Beth! Congrats on your new car! I have a Toyota Echo and I love love love it... Toyotas are definitely great and very reliable.
Anyway, re: the warranty, I'm probably not the most knowledgable person to ask here, but before you turn it down (if it's not too late now...?) I'd do a touch of research. You can find lots of review sites and message boards on the internet on which people talk about what needed repairs etc... Often you'll see things like 'this model usually needs a new part X after about 5 years'... or something like that. That said, Camry's are really good, solid cars. My parents had one for years and years with hardly any repairs needed. Still, I'd say do a little bit of research. You'd hate to get stuck. Also look into the cost of likely repairs though - it might be the case that the repairs will cost you less than the warranty.
You slid under a truck?!? That's bizarre because that's almost exactly what I did with my brand new car last xmas! It was a big honkin' pickup truck vs. my tiny little Echo. He stopped really abruptly at a light and I couldn't stop in time and - wham! - right into the back. But b/c of the size difference my hood went under the bumper. Which was probably good, because otherwise the whole front of the car would have probably been crunched, the windshield probably would have shattered and the airbags have gone off. Still, I paid through the nose for it in an insurance hike