Looks like I may just be getting my wish (see above)
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Latest news is that the franchise has been sold on to The Halcyon Company and they're planning on three new movies with T4 pre-production to begin soon and a release date at this point in 2009.
T4-6 will be Schwarzeneggerless and will be a new trilogy focusing on John Connor and friends battling against the machines in the future. Personally I hope they keep atleast the first one there and put time travel aside for a bit.
What are the odds that T6 will finish with John Connor sending his father back to 1984 in a last ditched effort to win the war and bringing everything nicely back the begining?