In a few weeks I a going to be taking a trip to the NASM Udvar Hazy center and I want to make sure I have a good lens for the job. I currently have a Nikon D60

Thanks for your help.

So you are looking for a good lens to buy?

Really depends on your budget?

I use an 18-200mm, it's great with the versatility it has, but it is not an inexpensive lens.

The 18-140mm looks promising if you want something in between the 18-55  and 18-200.

If you don't mind having 2 lenses/swapping, you could get the 35mm prime and the 55-200  vr or 55-300 vr.  You won't really need anything past 200mm, but I don't know if plastic mount (which is what the 55-200mm vr has) bothers you.

Sorry, I should have listed what I currently have. I have a 70-300mm and a 18-55mm but I'm more worried about lighting since most museums are dimly lit and this one frowns on tripods. I'm figuring I'd need some with the range of a f2.5?

Budget isn't much of concern. I don't wanna spend 2k or anything, but I'm not afraid to spend some coin.

Have you considered a prime? A 50mm f1.8 is quite inexpensive but good optically. If you want wider the sigma 35 f1.4 is getting rave reviews.

Really need to have an idea what focal lengths you contemplate needing to give better recommendations.

Are you shooting full frame or crop frame?  

If full frame, seriously consider a Rokinon (samyang) 14mm F2.8.  It is sharp to the corners and has great IQ.  It is a fully manual lens, but you can set the hyperfocal distance and shoot away.  At f4, it is something like 4 ft to infinity at the hyperfocal distance.

for a little closer to normal focal lenght, look for the Rokinon (samyang) 35mm f1.4.  It is SHARP wide open to the corners and gets even better stopped down to f1.8.  

Both of these can be had for very little money, compared to the excellent build quality and IQ you get.  They are currently my two favorite lenses.

Here are two threads with photo examples taken with these lenses.

Rokinon 14mm F2.8

Rokinon 35mm F1.4

I love my 35mm f/1.8 prime

The 18-55mm will do OK as these type of places tend to need a wide angle lens due to the lack of space to back up in.

The 70-300mm will be nice for any detail shots you are looking for.  Hopefully it is not Nikon's $180 version of the lens.

Since you are shooting a DX body, a 35mm in the f/1.4 to f/1.8 range would be good for lower light.

Mind your shutter speeds.  If you do not have steady hands, bump up the ISO as needed.  Better to have grainy pictures that can be fixed in post processing than to have blurry shots that cannot be fixed.

You could always just rent this sweet baby for $100.00 plus shipping.  

http://www.borrowlenses.com/product/Nikon_14-24_2.8

You will be fine with what you have.  While he lighting isn't as good as it is outside, it is still better than most other museum's.  I don't see you having issues with F3.5-5-6 lenses.  If you want you can rent a flash just in case, but your biggest issue will not be the lighting, but the people at the museum.

I advise you to get there as soon as the museum opens so you can photograph what you want, when the museum fills up it is hard to get good shots with people walking everywhere.

If you really feel like having another lens on hand, this is a good site to use:

http://www.lensrentals.com/rent/nikon/lenses/normal-range/nikon-40mm-f2.8g-af-s-dx-micro

http://www.lensrentals.com/rent/nikon/lenses/normal-range/nikon-17-55mm-f2.8g-ed-af-s-dx

I've been there a few times. Lighting can be kinda dim, so you definitely want something fast. If you're on a budget, Nikon should have a good fast 50mm lens for a bit over $100. A 35mm lens may be better if the D60 is an APS-C sensor camera.

A nice strong speedlight might help too, but I'm thinking it may unbalance the lighting. I'd prefer natural light.  You might also look into taking a monopod or a tripod. Not sure what they'll allow. I didn't try bringing in either the few times I went.

I'd probably keep the lenses you have and replace the camera.  D60 is very old technology and upgrading to a D5100 or D7000 will give you low light performance due to better useable ISO range.