hey Liza,
I know you have your heart set on the D700, but throwing your money away on that camera, and not having enough for at least one decent lens is like buying a Ferrari without the engine. Plus when you start talking about the D700, you're talking about more expensive lenses. Not that I'm saying thats a bad thing, but you're do sound like you don't have the money to get the lenses suitable for this Bad boy. Buying cheap lenses will like fitting a ford fiesta's engine into your ferrari.
Now Im not slagging off the cheaper lenses, some of them are good. However If you want an All-round lens thats versatile, you don't have the 17-55mm option going with the D700. The 24-70mm would be the ideal choice, but you're looking at $2500 for that. Do you have $5500 to spare?
The D700 is a great camera, but eventually it too will become antiquated eventually. There's no denying that with full-frame the lenses are expensive. There's no $210 18-55mm lens, because thats only for DX. Infact before 2007, all Nikon made was DX dSLRs. If you want a good camera that is cheaper, I think the Nikon D300s could be the one. it's cheaper, and this gives you leeway for a good lens.
As for the High ISO's the only time I think you really would want them, is for sports at night, thats the idea, why the D3s has 105,000 or whatever it is. so you can capture football in the worse conditions. If the object isn't moving then Darren's right using low ISO's is better. This photo was taken at ISO 100 with a 30 second shutter speed.
Well it all depends on what kind of wildlife you plan to photograph. if its Tigers, cheetahs, polar bears, panda's, even dogs. On a full-Frame camera you will want a 200-400mm VR or an 80-400mm. For Canon you will need the 100-400mm L. They are wildlife lenses, used for capturing animals, and also used for sports. If you choose the D300s you could look at cheaper alternatives, like the 80-200mm, or just get the 80-400mm, that way you could photograph birds as well. If you mean bugs, and insects than thats Macro, which would require you getting a Macro lens.
The reason why I say its a contradiction is because when it comes to lenses, landscapes, and wildife are at different ends of the spectrum. Getting a lens that does both is very hard, you end up losing on quality in order to achieve this feat. The lens would end up being so big, you would feel like your mounting a bazooka onto camera.
Landscape lenses are usually 10-20mm for DX, and 14-35mm or there abouts on full-frame. Wildlife on DX is about 100 - 400mm for full frame its about 200mm - 800mm. They're different ends of the lens choices you see.
If you were to get the D700 then maybe look at this setup...
Full-Frame system
Camera: D700 $3000
All-rounder: 24-70mm $2,500
Landscape: 14-24mm $2,300
Wildlife: 80-400mm $2,000
so thats what? about $7,500 -7,800.
DX system
Camera: D300s $1900
All-Rounder: 24-70mm $2,500 OR 17-55mm $1,500
Landscape: 10-20mm $650 OR 12 - 24mm $1,400
Wildlife: 80-200mm $1,300 OR 80-400mm $2,000
so even the most expensive option of two lenses is $6400. Ideally lets say you have 24-70mm and a 12-24mm thats $3,900. Even if you were on a budget, you could get the sigma 10-20mm and a nikkor 17-55mm and thats only $2,100 - less then the 24-70mm! and then you can get a D300s for $1900; totaling to $4000.