Best Nikon D40x Lens for Baby Portraits?

I have a 7-month-old daughter and the main reason I bought this camera is to take more professional-looking shots than my old camera could provide. I would like some advice as to whether or not I have a decent set of lenses for the job, and if I don't, what lens(es) could improve my chances of getting beautiful pictures of my little girl. I love soft backgrounds, but don't mind crisper backgrounds in some pictures. I want the focus to be on HER, though.
Here is my current set of lenses:

Tamron-F Zoom Macro 1:45 f=85~210mm (older lens from a 35mm film camera, does not auto-focus)
AF-S DX Nikkor ED 55-200mm 1:4-5.6G
Tamron-F 1:28 f=28mm (older lens from a 35mm film camera, no AF)
Nikkor 50mm 1:18 (I believe this is an older "kit" lens from a 35mm film camera)

Side note: I don't really mind that most of my current lenses don't auto-focus, and wouldn't mind if my future lenses didn't, either. But which option (AF or non-AF) is best for this kind of photography?

First of all, babies can't really pose, and they never stay still for very long. For this reason, I would recommend getting an AF lens.

Other than that, though, you have more than enough to take good, professional photos of your daughter. It really doesn't take much to take professional pictures of people. The more expensive lenses are really for things harder to photograph.

I'm assuming you want to shoot her in the crib or perhaps if she's into a high chair by now, there's always a good place, especially at meal time.

If you don't want to use flash but are will to add perhaps some day light you might consider the
35mm f/1.8 or the 50mm f/1.8 But if your little girl is anything my kids were, they won't sit still very long for a good portrait but you can certainly try.

The 50 is fine but it's more about lighting, posing and composition that it is about the lens.

If you are ready to spend money on something, I think it should be a Nikon SB700 flash. The bounce flash will give a soft available-light-like look, and it will eliminate motion blur.

The kit lens is absolutely perfect if you know exactly what you are doing. Leave it on AF. Babies don't know how to pose yet. To get blurred backgrounds, position the baby as far away from the background as possible then stay close to the baby as you shoot.

Do not attempt to shoot the baby with you two alone. There must be a third person with you to watch out for the baby in case she falls.

Your Nikkor 55-200mm should do just fine. The further away the camera is, the more blurry your background will be. (It has to do with how wide your aperture is.) Your 50mm lens will also give good results by the same token.

If the baby will be in one place (e.g.high chair), you should be able to compose on your manual focus lenses.

You might find a tripod and remote shutter release more useful than anything:
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