Tavel lens' to fit my Nikon D90?

I'm traveling for 6-24 months and am trying to buy some new lens' for my Nikon D90. I currently have the kit 18-55 and 55-200

Looks like the Nikon 18-200 is a definite

I'm still tossing up between the 35 & 50mm. Leaning towards the 50mm.

My only problem is now is ensuring that it fits on my Nikon D90.Am i right in thinking that any AF or AF-S will fit my D90?

Looking at purchasing this today 18-200 http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=4992&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=79

And then between the;
50 1.8 - http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=4911&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=79

OR
35 1.8 - http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=3173&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=54

What's the different between the AF & AF-S?
Is there much difference in the 1.4 to 1.8 to justify the price?

Why is this one so cheap? Http://www.citiwideonline.com/au/index.php?page=shop.product_details&flypage=shop.flypage&product_id=628&category_id=97&manufacturer_id=0&option=com_virtuemart&Itemid=79

Added (1). Thanks Taylor! So realistically there's no difference between the AF and AF-s for my Nikon D90? Also, do you think that the version 2 of the 18-200 is worth the extra money? As far as i can see, the only improvement is the focus creep.

Id go for the 35mm in addition to the 18-200 if you are going to get both. The 35mm comes in very handy in low light situations. 50mm is great for portraits and short telephoto, but too narrow for most other things.

My 35mm lives on my camera almost all of the time--it's that good.

1.8 is very fast for the money. The further you push performance, price goes up exponentially.

All AF and AF-S lenses will autofocus with your D90.AF lenses will not autofocus with the D40, D40X, D60, D3000, D3100, D5000 or D5100. Since you don't know whether or not you need a 35 or 50 you don't need either. Just get an 18-200. There are two versions of the Nikon 18-200 - the older is just the 18-200 VR and the newer is the 18-200 VRII. The price difference b/t the two is quite significant. Along with the 18-200, be sure to buy a genuine nikon en-el3e battery for your 90. Update - the newer 18-200 has the same glass, build quality and VR system as the old 18-200. But the newer version is built in THailand and the original was made in Japan. If you buy an AF lens, you will have no instant-autofocus override and AF lenses autofocus louder than AF-S lenses.