Get the 35mm 1.8. Seriously one of the sharpest Nikkor DX lenses made and it's one of the cheapest too.
I bought that lens last year. What a great lens! However you can't use it with a filter at night, pinpoint lights cause ghosting and flare. Just leave it without a filter and be careful.
Stuff I use- All Nikon lenses- 50 1.8, 35 1.8, 18-200vr, 10-24, and a Lensbaby Composer. Use the lens hood with all your lenses. It protects the front element, keeps rain and crap off, and adds noticeable contrast to your images, even when the sun isn't out.
I also use a cable release and a hot shoe bubble level. I don't use it too much but I also have an SB600 flash. I usually use a reflector if i need some extra light.
Get an extra battery!
As for tripods, you need three things, but can only get two- low price, light weight, and stiffness. Choose two. The rule of thumb is buy the best tripod you can afford, and carry the biggest tripod you reasonably can. Get a ballhead. I also put red and yellow Plasti-dip on my tripod feet, that way I'll notice if they're peeking into my shot.
As for bags, I hate all camera bags because even the so called incognito camera bags are overpriced and scream "camera bag!" I use a Seal Line messenger bag, with padded inserts. Rugged, water resistant, and I just look like a jerk with a bag.
A great place to get lenses is craigslist. People sell their stuff all the time. I see you only have a 55-200. If you want the other end other the focal range, pick up the kit 17-55 3.5. Really good quality, and inexpensive. Or better yet, get the 18-70, the kit lens that came with the D70. It one of the sharpest DX lenses out there. I wish I hadn't sold mine!
Sorry for the typos and weird sentences. I'm in the middle of a 24 hour shift. My eyes are crossing.
