Wget
Open Source
Wget is a free utility for non-interactive download of files from the Web.
ScrapBook
Open Source
ScrapBook is an extension for the Mozilla Firefox web browser which adds enhanced scrapbooking, page saving, bookmarking, and notetaking functionality.
Offline Explorer
Commercial
MetaProducts Offline Explorer is a Windows XP/Vista/7/8/10 program that allows you to download an unlimited number of your favorite Web and FTP sites.
HTTrack
Open Source
HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.
WebCopy
Free
WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.
Teleport Pro
Commercial
Teleport Pro is an offline browsing webspider.
Compare SiteSucker with alternatives
Compare ScrapBook and SiteSucker and decide which is most suitable for you.
Compare Offline Explorer and SiteSucker and decide which is most suitable for you.
Compare Teleport Pro and SiteSucker and decide which is most suitable for you.