What is your question? If you are asking for a recommendation, I'd get a bag big enough for whatever you plan to purchase for accessories.
What lens do you already have? Kit lens (18-55)? What do you plan to photograph down the road?
For flash, a typical flash would be the SB-700, but again.. without knowing what you want to photograph it's hard to guess. A SB-700 is still good to have in your bag.
I'd pick up a good UV Lens (it will protect your lens from scratched, dust, prints). I would also pick up a good polarizing lens.
A microfiber cloth for cleaning the lenLCD and lcd screen is good to have.
I'd invest in at least one extra battery and a spare SD card.
And just as important, a good book or two on digital SLR photography and exposure.
That will get you started.
Edit: I just realized this was in the Buy & Sell forums.. So, what are you looking for? What do you already have?