According to the November 2007 issue # 76 of the Official Xbox Magazine, Sony has secured the next Grand Theft Auto, which would be number 7 in the series, to be a true exclusive to the PlayStation 3. More after the jump.
Updates:
Rumor Buster: GTA 7 NOT Sony Exclusive
http://www.1pstart.com/rumor-buster-gta-7-not-sony-exclusive/