I've already mentioned the scene in "Catch me if you Can", where Leo DiCaprio's character peels the labels off of everything around him and saves them in his fake wallet - I SO wish I could've been on the prop team for that movie! To be surrounded by all those vintage labels, well - that's sheer heaven in my book (yeah, I'm a weird adult, too). :D
One of my favorite types of labels is food labels. I have some gorgeous vintage labels for sardines and vegetables - they're actually lithographed (I love that most of them say where they were litho printed, and of course they're all printed here in the States. How quaint). Some of the labels in my collection have raised illustrations - this kind of printing hardly exists anymore and when you do see it, it's expensive. I would bet that most labels today are thermal or laser printed.
Whenever I see food labels for cheap online, estate sales, antique stores or any other place I try to snap up as many as I can. If possible I try to get doubles of each label - one for using in my artwork and one for saving. You can get some amazing labels for pretty cheap if you know where to look - some of my favorite places are Manto Fev, Collage Stuff, and Paper Flea Market. The seller "inkpainter" on Etsy also has some wonderful stuff.
Here is some of my work that I've done using labels - as you can see, they're VERY versatile! :D