Hey,
To be honest I still find myself a comic book newb. But when I first started I went back to the originals. I have a few classic collections of Spiderman and Captain America (my two faves).
It was a great place to start to read them the way they were written when they first came out.
On a second note, I am trying to get a few more comics under my belt.... but I live in the desert and must rely on online shopping.
Can anyone recommend some must read comics?