Setting up file attachments in D6 for content types required a core module to be activated. You could sill add a CCK field for files or images or whatever, but the default attachment system (“Upload” module) was the place to go and often one of the easiest.
In D7, there is no Upload module! It took me a while to realize (and checking a few posts to be sure) that the Upload module was deprecated in favor of the new Field API. In other words, if you want to add a file attachment in D7, then you need to add a file field to the content type.
I know its not really that much news… and that adding a file field is a relatively obvious solution. But - its a good example of how changes between D6 and D7 have made things easier and cleaner. It also made me feel better to know that there wasn’t something I was missing… like a whole core module.