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You have not said how experienced with flash you are. Learning to use a new flash is tough enough, adding the wireless makes things much more complicated.
If you use the SC-29 cord there is less to learn, at one time. It gets the flash off camera within the length of the cord.
As to which flash, I would get a Nikon from KEH, SB600, 700, 800, or 900.
I lucked out and got a SB600 at Best Buy when they were $149.
I use a SB-26 as a slave on manual for fill purposes, from KEH. These work great with my D7000.
I follow the KISS principle whenever possible.