I really don't know a lot about Macro lenses. But see these links: Link 1, Link 2, and your best friend: Google.
I think the 18-135 is worth the investment. It has a longer focal length that would let you take some pictures that otherwise you may have trouble taking with the 18-55 lens.
Differences between D40 and D40x:
- The D40x has 10 megapixels
- Lower ISO capability. From 200 (D40) to 100 (D40x)
- Faster continuous shooting rate, from 2.5 fps to 3 fps
- But the D40x has a slower flash sync, of 1/200. Instead of the 1/500 of the D40.
Wow... super helpful, thanks... and how about for my edit of my last post? lol
(About the D80)