What are the differences between most Christian Bibles and Jehovah’s Witnesses Bible? Are most Christian bibles and Jehovah’s Witnesses Bible the same ? If not what are some important differences in them?
The main difference between the New World Translation (NWT) and other Bibles is that the NWT has attempted to eliminate almost all references to the divinity of Jesus in the New Testament.  Another obvious difference is the introduction of the name ‘Jehovah’ into the New Testament.  This is also an attempt to deny that Jesus is God.
The King James Version text is based on the ‘Textus Receptus’ which is not used by the New World Translation, the New International Version, the New Living Translation or the English Standard Version.  The NWT Christian Greek Scriptures (New Testament) is mainly taken from the Westcott and Hort translation, but has been altered and changed to support the views of Jehovah's Witnesses that the pre-mortal Jesus was created by Jehovah and that Jesus is not part of the One Being of God.
It is true that Jehovah’s Witnesses do not believe in the Trinity and they do not believe that Jesus is God.  See Section IV, V, and VI in the following article by Dr. Bruce M. Metzger, who was professor of New Testament at Princeton University.  The article also looks into the history and background of the New World Translation:   http://www.bible-researcher.com/metzger.jw.html
Here is a partial quote from an article that examines the background to the translators and the editing of the New World Translation and provides examples of the NWT anti-Trinitarian bias:

“New Testament, 1950. Frederick W. Franz, ed., New World Translation of the Christian Greek Scriptures Rendered from the Original Language by the New World Translation Committee. Brooklyn: Watchtower Bible and Tract Society, 1950.
Bible, 1961. Frederick W. Franz, ed., The New World Translation of the Holy Scriptures, rendered from the Original Languages by the New World Bible Translation Committee. Revised A.D. 1961. Brooklyn: Watchtower Bible and Tract Society of New York, 1961. The Old Testament was originally published in parts from 1953 to 1960. The whole was revised for the one-volume edition in 1961, and subsequently revised in 1970 and 1984.
The publisher of this version has never made public the names of the translators. But former members of the Governing Body of the Jehovah's Witnesses organization have identified the members of the committee as Nathan H. Knorr (President of the organization), Frederick W. Franz (Vice-President), George D. Gangas, and Albert D. Schroeder. According to Raymond V. Franz, the &quot;principal translator of the Society's New World Translation&quot; was Frederick W. Franz. (1) According to M. James Penton, &quot;to all intents and purposes the New World Translation is the work of one man, Frederick Franz.&quot; (2) Franz afterwards became the President of the organization, from 1977 to 1992, and was responsible for the revisions.
The Forward to the first edition of the New Testament (1950) explained the need for the version, and also indicated the reason for its name: &quot;It befits the significant time of transition from the old world to the righteous new world that translations of the Scriptures today should as far as possible eliminate the misleading influence of religious traditions which have their roots in paganism.&quot; (p.7, emphasis added.)
The New Testament adheres to the text of Westcott &amp; Hort. It is a fairly literal translation, for the most part, but it does have some peculiar non-literal renderings. These are the result of the committee's efforts to conform the version to the doctrines of the Jehovah's Witnesses. &quot;Jehovah&quot; is given as a translation for kurios (Lord) in the New Testament whenever the Father is meant, but not when it refers to Christ, the Son. &quot;Torture stake&quot; is put instead of &quot;cross&quot; because the Jehovah's Witnesses believe that the cross is an idolatrous symbol introduced by the Roman Catholic Church. And because this sect teaches that Jesus Christ was merely an angel, the version shows an anti-trinitarian bias in several places.”

Examples of Anti-Trinitarian bias then follow.   http://www.bible-researcher.com/new-world.html
Here is a short extract from the article ‘The New World Translation - What the Scholars Really Said’:

“The Watchtower and Jehovah's Witness apologists have often cited scholars in support of the New World Translation in general, and particularly its rendering of John 1:1c (&quot;and the Word was a god&quot;).  Scholarly citation is a form of an &quot;argument from authority.&quot;  Such an argument cannot establish the truth or falsity of a given assertion; it can merely lend credence or cast doubt.  Sound arguments from authority will consist of an accurate quotation from the scholar in question, which entails insuring that the context of the authority's statements are consistent with the argument being presented, and that contrary statements in the same passage are not removed with creative use of ellipses (&quot;...&quot;).  Further, the scholar must be a recognized authority in a field that pertains directly to the assertion being made.
When Jehovah's Witnesses produce scholars that support the NWT, we must first establish that the scholar is, indeed, a recognized expert in the field of Biblical Languages, and that he or she has been quoted accurately.  When given careful consideration, many of the scholars used by Jehovah's Witnesses do not actually constitute a sound argument from authority.  I'm not suggesting that no scholars may be found in support of the NWT or its translation of John 1:1, but these are in the minority and often are not as qualified in their field as the scores of scholars who advocate the traditional translation.”

The chart that follows examines how some scholars have been used in defense of the NWT and whether they actually support the Watchtower translation as claimed: http://www.forananswer.org/Top_JW/Scholars%20and%20NWT.htm
Readers are at liberty to study the articles referenced and to draw their own conclusions.