If you want to save webpages as pdf documents or webarchives for archiving purposes or if delicious isn't enough and you just need a local copy and not just a bookmark, there are several ways to easily do this in OS X.
Most of the time I've been using Together with its pdf and webarchive bookmarklets or a shortcut. I guess other apps like Yojimbo have similar features. There's one downside however. If you want to clean up the page with something like Readability before saving it (which I like to do, to keep the size down), apps like Together won't see these changes, since they download the url directly.
Time to turn to OS X's print functions. In your favorite browser (I use Safari), press cmd+P and you'll find an option in the print window to save stuff as pdf (in the lower left corner).

You probably already know this, and this isn't the main point of this post. What you might not have known is that you can assign a shortcut to this function, which is what I was searching for after having switched from Together's save as pdf feature, since this saves time.
All you have to do is assign a shortcut in the keyboard preference pane, as detailed in this Mac OS X Hint (takes 15 seconds to set up).

I assigned cmd+P, so now if I am on a page I want to save, I (hit the readability bookmarklet, which automatically and instantly cleans up the page and) press cmd+P twice and have a nice archived version.

So this might also come in handy for people not having one of those mentioned programs and not liking to waste time with the mouse to make use of this feature.

(Note that this does work with the "Save as PDF…" menu, but not with the ones below the line. Apps like Together, Evernote, Shovebox etc. have a print pdf function there too, but you have to click the pdf button once before shortcuts for these menus will activate, which makes a shortcut for them kind of pointless if you have to use the mouse before.)