An option is a canon 350D body with a pair of lenses... an 18-55 IS(note the IS, not the shitty normal 18-55) and a 55-250 IS or the Nikon D80 with an 18-135. Both will come to roughly the same price. The canon lenses are image stabilized and will offer atleast 3 stops of compensation because of that.
The 400D is actually a downgrade over the 350D in my opinion. Other than the extra 2 megapixel, it offers nothing else. The secondary LCD is gone, the ISO noise is higher and its frankly not worth the higher cost.
Out of those, the canon is better as the lenses are far superior. But the D80 is a better body.
You do not get 10x or 12x or whatever zoom as all those zoom lenses are inherently a compromise. The basic idea of an SLR is changeable lenses and better the optical quality of the attached lens, better the images. Lenses with very high zoom ranges like the ones on prosumer cameras are only average at any focal length.
The D40 and D40x are sad cameras. They don't have an autofocussing motor in the body and hence can't autofocus all nikon lenses. Plus it has only 3 point AF, no DOF preview and the viewfinder is quite bad. Both the sensors are noisy. One should get a D80 at the very least if one wants nikon.
However having said all this, neither of these cameras will fit in 20k-25k. In that budget, better get a point and shoot.