Bible Gateway features not just one Bible, but many different versions of the Bible. Each of these versions represents a different translation (or in a few cases, a paraphrase) of the Bible. Many of these versions are translations of the Bible text into different languages. Some languages (particularly English and Spanish) have more than one Bible translation. These Bible versions are all considered to be the same Bible at heart, but differ in translation style: some Bible versions use flowery, old-fashioned language, others more modern language, and some tailor their language for a specific reading audience (such as children or non-native speakers who benefit from simpler sentences and vocabulary).
There is no Bible version that is universally considered the "best;" your choice of Bible versions is a personal one based on your own personal preferences. It may take you some time to settle on the Bible version that you prefer, but most Bible readers eventually settle on one or two favorites. If you don't choose a particular Bible version, Bible Gateway presents you with the New International Version (NIV), a common and well-regarded English version. If you want to learn more about different Bible versions, read What About Bible Translations?, which will walk you through this question.