i agree with slau...
the d40 is (IMO) a crippled version of it's older brothers in the d-series. i'd go for the d70s or the d50, unless you're on a budget that you cannot break and you must have a camera immediately. i think the extra cash will give you enough room to expand your abilities as a photographer, because even if it's a hobby, you might actually enjoy it much more than you thought and pursue it farther than your expectations.
also, for landscapres, you might want a wide-angle lens (under 20mm focal length) to capture the entire scenario. otherwise, you'd have to settle for panoramic shots with a tripod. 55mm field of view on a cropped camera is really limiting to how much area your lens can cover.
and though you may be able to pull off closeup shots with the telephoto end of the 55-200 lens, you can get far better results from a dedicated macro lens. granted, you're on a budget, so buying one is probably out of the picture. but just mentioning it for the sake of mentioning it

i think the 18-70 would make a fine starter lens. or if you're ready to invest a little more, consider the sigma 17-70 lens (~$400 US). the sigma lens offers a little bit of wide angle and a little bit of macro. it's also very fast on the wide end, perfect if you take indoor shots.
whatever path you take, i hope you have lots of fun! happy shooting!