Good travel lens for my Nikon D7000?

I was wondering which lens is lighweight, affordable, and has decent quality?
I was thinking that maybe one of these, but they don't have a zoom:
- Nikon NIKKOR AF-S 50mm f/1.8 Lens
- Nikkor AF-S DX 35mm f/1.8G Lens
- Nikon AF-S DX Micro-NIKKOR 40mm f/2.8G

I was thinking about purchasing one of these lenses and bring my 18-105 kit lens on vacation. I really want to take quick night photos as well (meaning that you can raise the shutter speed because of the smaller aperature value)
What are your opinions? Will that be enough?

I have several zooms and fixed lenses on my d300. I like the 35mm as a general prime lens, with the DX crop factor it is more like a 50mm and while you're limited with lack of a zoom, it forces you to get creative and move your body around to compose great photos. It works great in low light, just mind the very very shallow depth of field at 1.8 (not great for portraits at 35mm and that wide of an aperture). Landscapes, cityscapes, detail shots it's a great lens and a pretty good price too.

I own the AF 50mm, and the 40mm micro, as well as previously owned the 35mm.

I disliked the 35mm because of the slight amount of perspective distortion (that all wide angle lenses have). And there's hardly any shallow DoF at 35mm, even at f/1.8. That is a myth. The short 35mm focal length kills any semblance of a shallow DoF. If you are looking for shallow DoF - avoid the 35mm.

Here is a page with DoF charts. You can see that as the focal length is reduced, the DoF becomes wider, regardless of aperture.

http://www.althephoto.com/concepts/selectivefocus.php

I have the 40mm just for macro. My main macro lens is a Tokina 100mm lens, but I like the shorter 40mm macro for certain situations. And while the 40mm is not as fast as the 50mm (1 1/3 stops slower), it does have macro capability - so it depends on what you really want to use the lens for.

Of the three - for low light capability - I prefer the 50mm. Other folks will prefer the 35mm for cropped cameras, so the best thing is to visit a camera store and loo at both.

The other advantage of the 50mm is it is a full-frame lens, so if you ever have the thought of upgrading (D600 etc), then you can keep the 50mm, whereas you would have to sell the 35mm as it is a DX lens (as well as the 40mm).