Which camera lens for my Nikon DSLR?

I'm looking to buy a lens for my Nikon DSLR, it's a D3100 and I don't have a lot of money. I think I've narrowed it down to a 35mm AF-S or a 50mm AF-S. This will be the first lens I will be buying outside of the kit lens. I do very basic photography of my family, sometimes I like to take real close up pictures of my kids.

Which lens would you recommend for my situation? What about filter recommendations? If you've got a filter you love, let me know that as well!

Thanks in advance!

Added (1). Tape it with masking tape or duct tape?

Do you find yourself shooting @ 50-55mm or towards 30-35mms? Tape your 18-55 to 50mm for a week or so and then do the same @ 35mms and see which is more useful. Scotch or painting tape. Don't use duct tape…

I think you should try out the Lynny Lens System. It's a universal lens, similar to the Lensbaby. It's a selective focusing lens that you push and pull to focus and tilt all around to control the creative zooming blur around the photos.

There are different models available, including a lite version and a Pro, and for those two versions, there's a macro version for extreme macro shots, and also a close up version for distances in between the normal version and the macro version.

It's the most amazing lens out there, and is really fun to use, as I'm the creator and designer, and I don't use my other lenses, I just use my Lynny lens. It's so fun to use.

But I think that this is a great lens to get, and is cheap in price for what it does. Check it out.

I suggest you get the 50mm. If you can afford it, the 50mm f1.4 is a fantastic lens. The only filter I use is a polarizer, everything else I do in post. Get extension tubes for extreme close ups.

Different lenses are for different uses… Consider 24-85mm or 50mm f/104

I'm a canon user, so I can't say which Nikon lens but all lenses have certain characteristics so you may find some of this useful.
If you are photographing people, portrait style, you generally use something in the line of 70-200mm. The reason for this is that wider lenses produce distortion and can pull faces out of shape. While there may be times this looks great, as a general rule all is does is make noses, ears and other parts of the body look larger or smaller than what they are. Not very flattering.
The longer lenses have the benefit of producing none of this distortion. The effect of a longer lens is compression of the image producing a lovely soft back ground that makes the subject stand out. This will be effected by the camera settings though I won't go into this here.
If you are doing more scenic shots of the family the the 35-50mm range will be good as it is more in line with a landscape that simply has people in it!
Have a look at the link provided to get an idea of what longer and shorter lenses can do, see if you can spot the differences between them.
The choice is going to depend on what you think will be used most or what you enjoy most.