I would suggest renting an ultra wide zoom for your Nikon for a week and shooting it set at various focal lengths. I think they have a 17-35 f/2.8 if my memory serves me correctly.
How useful any of these lenses will be really is up to you. Another reason to try out a wide zoom rental.
Personally, I love 35mm and 28mm for many things, but for my average shooting, I find even 35mm to be frustratingly wide for many subjects if I have it as my only lens at the time. Wides really make you move closer than normal if you are after a "normal" subject size/magnification/whatever you want to call it. One of my favorite setups is one camera with a 35 and another with an 85, or one with a 50 and another with a 135. If I am using a super wide, I really prefer to have three cameras on me. One super wide (pref. a zoom), one normal, and one mildly long tele, like a 100 or 135. That is my normal wedding setup for the candid stuff...
...but it really does you no good to know all that about ME.