I used the Nikon free stuff for my first 4 months of shooting and got along fine. My brother suggested I download a trial of Lightroom (3.6 at the time) and my life was forever changed. I've said it before, and mounds of software trials and purchases later I'm still convinced that if I could only use one piece of software Lightroom would be it. Optimally, I think the Photoshop CC offering is an amazing product, even if you just ease into Photoshop, and the Nik tools would be my first choice for something on top of them.
Why Nik? Two things. One, Control Points. Nikon Capture 2 used to have them, and they are a color/luminance based way of isolating an adjustment. Two, pay once - period. I purchased the Nik Collection in 2012 and have never paid for an upgrade. I purchased the onOne Perfect Photo suite in 2013 (version 8) and just received my promo for version 10, each upgrade costing more or less what I paid for Nik, and honestly, outside of the mask and portrait tools in there I could live without the rest (and those as well - but I have 'em).