There are very few differences between the D60 and the D40/x. They're the same weight, work the same, same body. However, the D60 has a few perks over the D40/x, being a newer camera. The main one is anti-dust systems, which is pretty useful to have inbuilt instead of having to pay for a technician to clean it for you (it's not full proof, but at least it helps).
If you were going to go for a D40, I would have recommended getting the D40x, however now that I've looked at the prices on Amazon I've found that the D60 is cheaper than the D40x so definitely go for the D60 over the other two.
I'm going to add one more complication to your list: for the about $50 dollars more than the D60 and ~$30 less than the D40x, why not get the D80? Yes it is an older camera without the anti-dust systems, however it has become a lot cheaper now that the D90 is out and sports a couple advantages over the others. The first one being that it has two control dials instead of one (one at the front and one at the back) but that only really helps if you're shooting manually. The second one is that it has an inbuilt servo-motor, one of the main (and controversial) reasons why the D60/40/x were cheaper than the D80 to begin with. If you're looking on getting some good lenses then the inbuilt servo-motor adds a lot more compatibility and, thus, a lot more lenses to your list of possibilities --the D60/40/x are limited to AF-S, AF-I lenses only.
As for what lenses you would want to look at buying. It all depends on what sort of result you want. I have seen some brilliant architectural photography taken with super-wide-angle lenses. I know Nikon make a 14mm 2.8/f and a 12-24mm f/4, so I'd recommend having a look for them to see how they compare. Lens mounts hardly ever change, so consider a lens as a long time investment and it's worth spending good money on.