The first obvious choice is to buy a printed version that contains over 400 featured articles in a hefty 5,000 pages book. Of course, this represents only the 0.01% of the English version of Wikipedia and it is a little bit too big to carry around with you.
The second choice is to use the magnificent application called Kiwik! This tool allows you to download various different language versions of Wikipedia and search, read, bookmark anything you want offline!
Using a powerful search tool, you can find Wikipedia sets or other kind of web content sorting and filtering by date, publisher, language, and author.
I downloaded the Venezuelan edition for practical reasons, but the English version is also relatively small (9.6GB).
Kiwix uses the ZIM file format that is an open file format that stores wiki content for offline usage. Its primary focus is on the contents of Wikipedia and other Wikimedia projects. The format allows for the compression of articles, features a full-text search index and native category and image handling similar to MediaWiki. Unlike the native Wikipedia XML database dumps the entire file is easily indexable and readable using a program like Kiwix. – source: Wikipedia
Using Kiwix is as simple as downloading, unzipping and running the binary found inside the newly created folder. Give it a try! You never know when/if you’re going to need it :)