The following 17 complete verses are missing in the NIV, and in most modern versions:
• Matthew 17:21
• Matthew 18:11
• Matthew 23:14
• Mark 7:16
• Mark 9:44
• Mark 9:46
• Mark 11:26
• Mark 15:28
• Luke 17:36
• Luke 23:17
• John 5:4
• Acts 8:37
• Acts 15:34
• Acts 24:7
• Acts 28:29
• Romans 16:24
• 1 John 5:7
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Besides these verses, many more words are missing, though the entire verse is not gone.
In fact, the NIV Bible has more than 60,000 less words than the KJV! Below are a couple references for word counts for the KJV, and then one for the NIV.
KJV: 788,280 (1769 edition of the 1611 King James Bible):
http://www.biblebelievers.com/believers-org/kjv-stats.html
KJV: 788,258
Laurence Vance, King James His Bible and it's Translators, p. 74
NIV: 727,969
http://wiki.answers.com/Q/How_many_words_in_NIV_Bible