Back in the pre-ubiquitous internet days, services like AvantGo allowed you to cache and store websites for offline viewing. These days there's little need for that kind of thing, simply because we're very rarely offline.
Having said that, there are times when a solid internet connection just isn't available and it would be nice to keep on working, reading or browsing sites. That's where a program like SiteSucker comes in.
SiteSucker, as the name suggests, sucks down a localized version of site of your choice to your Mac's hard drive for viewing offline. Simply type in the URL of the site you want and press "Download," SiteSucker will do the rest, scanning, downloading and processing the site into an offline viewable form for when you haven't got an internet connection on hand.
The number of levels deep SiteSucker will scan and download can be user defined, so if you're looking for a small skim of the site, a one or two level archive will do. If you want a more in depth, browsable localised site something more like a four to six level download will probably be best. You can also set limits on the number of files downloaded, the minimum and maximum file size as well as a minimum image size to download. File type limits can also be imposed as can paths to include or exclude, and whether or not to limit it to the original site's server.
Once you've got your site downloaded, it's just a case of opening it up in Safari or any other browser of your choice from your disk.
If you've ever wanted to keep an offline version of a site for tinkering, browsing or analysis, SiteSucker gets the job done fast, efficiently and automatically, all for the great price of free from the Mac App Store.