It looks to be pretty much the same as N82 except with no flash but slightly better battery and, IMO, better design. It's lighter, not quite as thick and buttons look much more comfortable. It also got a FM-transmitter, so you can listen to your music on a radio. It's also built on Feature Pack 2 as opposed to FP1 as in N82, and it's supposed to be smoother.
I can live without the flash, I don't take many pictures anyway, so it looks like the N79 is the better option for me, as long as it's released soon.