Kerbouchard, I have already bought SB-700. Flash is primary thing in photographing.
Ok. Why I wrote on this forum? Because I need a solution. If everybody say that D90 is better than D5100, it means I buy D90.

So, here is another problem. I need some lens for it ( 2 variant ):
- 18-55 and 50mm/1.8D
- 18-105
What you think?
Well, crap, that means I just typed my entire last post for nothing.
Ok, we'll start over. What are your goals? You seem to be all over the place. In your first post you mention a fisheye lens, but you seem to have a overall preference for people photograpahy. A fisheye lens, IMO, is a gimmick lens good for a few different shots, but definitely nothing to do a complete shoot with.
Ok, so you have an SB700, I assume you know it has the ability to be used as a remote flash with the appropriate camera body(D90/D7000/D300/D700/etc). Using and learning off camera flash is enough to keep you from getting bored for a while. I have the 50mm 1.8. I love it. Heck, I use it a lot when I am assisting in weddings. It is a lens I think everybody should own. The 18-55 is a lens I have never owned and see no value in, so I can't give you good advice on it.
I'll tell you my photo journey, and you can pick and choose as you like.
My daughter was born two years ago and I wanted to take great pictures of her growing up. There weren't a lot of me, and I wanted her to have her history. I bought an expensive P&S...paid about $300 for a Samsung HZ-10, I think it was...It sucked indoors and that was the type of photos I was taking. Next, I decided to buy a D90 kit. It came with the 18-105 and the 70-300. I quickly realized I still couldn't take good pics indoors. I researched and found out that I needed a 50mm 1.8, so I bought it. Now I could get the shutter speed high enough to not have a blur of a subject, but focus was too shallow and I couldn't take the kind of photos I wanted. Then I decided to buy an SB-600 and learn bounce flash...Now, I can effectively shoot a moving subject indoors with whatever lens I choose and I am happy with the results. Since then, I have added a manfrotto tripod, a 35-70 2.8(for around $300), a Sigma 150 2.8 Macro, an SB800(around $300), reflectors, softlighters, umbrellas, stands, etc, and feel I can shoot pretty much anything.
It took me longer to get where I wanted to be than I wanted it to, but now I am assisting in weddings, doing some pro stuff, and getting the quality images of my daughter that I wanted. I will pick up a full frame Nikon when they release it and will move on from there.
There is always more that you want...The important part is to start with what gives you the most options, so as a very long way of answering your question, I would go with the D90, with the 18-105 coupled with your SB700. I just feel like it gives you more options. The next thing I would pick up would be a 5 in 1 reflector...and then the 50mm 1.8. After you have figured out those toys, you should have a pretty good idea of what you want to upgrade from there, and probably won't be needing to ask us what we think. You will know where your limitations are and will know what you need to overcome them. Oh, and save a few bucks for a library card. There is a wealth of information at the local library or half priced books. Don't worry so much over the name or the author. There are a few people on this forum who will tell you that you have to start out with Understanding Exposure by Bryan Peterson...heck, I've never even seen the book, and don't care to look for it. Exposure is easy, and I don't need to buy a book to understand it, but a few of my personal recommendations is anything by Rick Sammon(he has an enthusiasm for photography that comes through in his writing) or Light, Science and Magic.
In any case, it's more important that you can identify with the style of the author than what I think of a certain book...Just pick a book that you think you will read and go from there.